|“||Each one hated the other, because each one feared the other, because each one knew something about the other.||”|
— Carla Grunwald about Monison
Monison is the friendship and rivalry pairing between Mona Vanderwaal and Alison DiLaurentis. Both women spent a portion of their lives torturing each other, Alison as a bully in High School, and Mona as the infamous stalker A. Their current relationship is complicated, as they have a very tumultuous past.
The relationship between Mona and Alison is a tumultuous and complicated one, primarily due to each others behavior in High School. The relationship started off antagonistic, as Alison bullied and treated Mona poorly in their first few years of High School. Mona, desperate to fit in, often hung around Alison and her friends, only to be rejected by the group and humiliated by them a number of times. Alison even nicknamed her, Loser Mona, and turned the school against her. She bullied her and treated her poorly out of amusement. This angered Mona and she started sending Alison threatening messages and texts under the alias, "A", in an attempt to scare her, which she succeeded in doing. However, she never really wanted to hurt the other girl. One night, Mona was out for a walk, when she saw whom she believed was Alison walking alone. Mona was so overcome with rage and anger towards the girl who had made her life a living hell, that she hit her over the head with a shovel. This was later revealed later to not have been Alison, but Radley Sanitarium escapee, Bethany Young. Mona later helped Alison disappear, and became A to torture Alison's inner circle, and eventually Alison, for how they treated her. After Alison returned, their relationship worsened, with Mona even framing Alison for her death. Alison was then sentenced to prison for the murder, but was eventually being released when Mona was discovered to be alive. Five-years-later, they no longer have an antagonistic relationship, as they have reached a mutual understanding. However, their relationship is later strained even further when Mona confesses to killing Alison's cousin/adoptive sister, Charlotte, in self-defense. Even though Alison originally wanted to turn Mona over to the police, after a year went by and Mona sought treatment at Welby, the two are able to be cordial with one another when in the same room. However, they don't trust one another, as they both know what the other is really capable of.
|“||Oh my gosh, can't she get a freaking clue? What a loser!||”|
— Alison about Mona in Pilot
In a flashback, Alison and Aria are walking down the street, eating ice cream and giggling to themselves. Mona walks behind them and spots them, yelling out to them repeatedly to the point where they could definetly hear her. Alison asks if Aria hears Mona, and ARia thinks they should wait, but their pace only quickens. Alison asks Aria if she's ever going to a get clue, and calls Mona a loser. Mona continues waving and shouting in an attempt to get their attention. Alison takes Aria's hand and the two go around the corner and start running, laughing about how they managed to ditch "Loser Mona". Mona watches them run away with a sad expression on her face. She crosses her arms over her chest and turns, walking in the other direction looking sad and disappointed.
Hanna mentions that Mona is the way she is because she wants people to forget about the geek she used to be, the one that Alison turned her into. Later, Mona continues to call Lucas Gottesman by the nickname that Alison gave him, Hermie. She is also determined to remain on the top of the social-ladder, not wanting to fall back down to where she was as Loser Mona.
|“||If you ignore it, it will go away.||”|
— Alison about Mona in The First Secret
"The First Secret" is an episode that takes place prior to Pilot, specifically Halloween 2008, during the height of Alison's reign and Mona's social inexistence.
At lunch, Mona excitedly walks up to the Liars' table with a lunch tray, greeting them happily. Alison cruelly states that if they ignore it then it will go away, degrading Mona down from a person to a thing. Mona is hurt by this and walks away to sit at another table where Lucas Gottesman, another one of Alison's victims, happens to be sitting. After school, the same scene from the pilot plays, in which Mona attempts to get Alison and Aria's attention and they rudely ditch her.
At school the next day, Lucas Gottesman runs into her, spilling his juice down her white pants and on her new shoes. He apologizes and tries to wipe it up, but she snaps at him not to touch her. She starts degrading him, calling him a "hermie" and picking on him about the rumors that go around about him being intersexual. All the while, Mona watches awkwardly at the other side of the hall. Lucas looks at Mona who gives him an awkward smile, and he assures her that one day, Alison will get what's coming to her.
At a Halloween party that night, Mona is dressed as cat-woman while Alison is dressed as Lady Gaga. Mona walks up to her and gives a, "meow", which makes Alison smirk. She asks if she knows her, but Mona says that she doesn't - but she will, before walking off. Alison watches her go with a smirk, before returning to dancing. A little while later, Jenna Marshall, who is dressed as Lady Gaga as well, walks away from Alison where the two had just argued. Mona meets up with Jenna shortly after, and tells her that she's the best Gaga there, with Jenna telling her not to tell Alison that. Mona claims that Alison doesn't scare her, and the two make introductions, seemingly forming a friendship and possible future alliance.
At the masquerade ball, Mona talks with Spencer who tells her that she's a great friend to Hanna. Mona is thankful for this, and mentions that because of Alison she went years without having any friends. Spencer apologizes for never standing up to Alison all those years ago, and Mona lies by saying that she stopped thinking about all that stuff a long time ago but that day, she couldn't get Alison out of her mind. Mona mentions that she took Caleb to a little store in Brookhaven, and Spencer recognizes the name. She goes on to say that it was last place she saw Alison - a week before she went missing.
In a flashback to the store in Brookhaven, Mona spots Alison looking out a window and, despite her wearing the Vivian Darkbloom costume, she recognizes her. Ali mutters, "crap", under her breath and crosses her arms over her chest. Mona is excited that Alison is there, and mentions that it's almost as if they're shopping together. She notices that Alison is staring out the window and asks her name, but Ali holds up her finger and "shushes" her, which makes Mona flinch and become confused. She asks why she is dressed like that and what is going on, before excitedly asking if it's some sort of a game. Ali asks her if she can tell her a secret, which excites Mona who asks if she's for real, and Alison assures her that she is - but it's also for keeps. Mona is overjoyed that she is talking to her, and Ali admits that she's watching someone which makes Mona curious and look out the window. Alison moves her backwards a bit and tells her that it isn't a game, and tells her to pretend like she doesn't know her and take off. Mona uses this as an opportunity to finally get the upper-hand of Alison, threatening to tell if she doesn't get what she wants. Ali asks what it is she wants, and Mona admits with a slight smile that she wants to be popular which makes Alison smirk before giving her a number on the back of a post card from the Lost Woods Resort, before Mona leaves the store.
Back in present day, Mona tells Spencer that she tried to call Ali the next day but she went M.I.A. and she never heard from her again. When asked if she saw whom Ali was spying on, but Mona claims that she didn't but she figured it was some guy that she was crushing on. Spencer realizes that A wasn't watching Alison in Brookhaven, Alison was watching A, and Mona stops her saying that she doesn't understand. Spencer tells her that Alison checked into a hotel the morning before she went missing but she didn't go there to hide from A, she followed A there. Mona is surprised to hear this.
Once Spencer and Mona find A's lair at the Lost Woods Resort, they discover that it is covered in pictures of Alison and articles on her disappearance. There are collages, dolls, wigs, and cut-outs of Alison all over the lair along with other pictures and information on the other Liars, although they are mainly interacting with Alison. In the lair, Spencer also finds Alison's diary which A had stolen. The lair is revealed to really be Mona's, as she is A and had been the one torturing and stalking both Alison and the Liars.
Mona kidnaps Spencer after revealing herself as A, and Spencer believes that Mona didn't see Ali in Brookhaven - Ali saw her. She believes that Mona made the story up, but Mona disregards this leaving it unknown. Spencer asks her if the whole A-thing was payback for them letting Alison treat her that way, but Mona claims that she's over Ali and that she was never Mona's friend, but Hanna was.
While admitted to Radley Sanitarium, Mona is visited by Hanna, who has been visiting her for the last few weeks. However, due to the amount and type of medication that Mona is on, she is hallucinating Alison dressed as Red Coat. On one occasion, she smiles at Alison who is sitting in a chair in room at Radley, reading Lolita smiling back at her. Unbeknownst to her, the chair is actually empty.
|“|| Mona: I'm scared for you, Alison.|
Alison: I'm scared for me, too.
— Monison in a flashback in A is for Answers
Emily confronts Mona about her working with Ezra Fitz, and they discuss his book. Mona wanted to stop his publication of some of her illegal activities, and Emily asks if she read the book and the parts about Alison. Mona comments that if Alison were alive she would love to be the focus of his scandalous expose, but she only ever saw the parts of the book that she was in and never the full thing.
Alison tearfully explains what really happened the night that she disappeared, and talks about Mona's involvement.
In a flashback, Alison escapes from Carla Grunwald's care after the latter pulled her out of a grave that Jessica DiLaurentis had buried her in. She is walking down the street in somewhat of a trance, when Mona, who is driving by, notices her. She calls out to Alison worriedly, and Ali looks at her. She is covered in dirt with her head bleeding, causing Mona to ask if she's okay, and Alison to look at her tearfully.
Mona gives Alison a ride back to the Lost Woods Resort, where she runs a rag under water. She then presses it against Alison's head-wound and helps her clean it. Mona is still shocked that someone tried to kill Alison, who is worried that someone followed them since no one can know that she's there, but Mona assures her that they are alone. She registered using the name Vivian Darkbloom just as she had said too, and reveals that she's scared for her. Alison admits that she's scared for herself as well. Mona coyly asks that if A had enough courage to try to bash her head in, then nothing is stopping them from trying again, which Alison fearfully agrees to. Mona eerily suggests that maybe she should die, which frightens Alison. She then clarifies saying that she should let A think she's dead by disappearing, before telling her to rest and laying her back on the bed. She strokes her face and tells her that things will work out the way they're supposed to, and she'll take care of her before giving her a kiss on the forehead. In the room next door, Mona hums while brushing her Alison dolls hair before placing it in a dollhouse.
The next morning, Alison is getting dressed as Vivian Darkbloom, preparing for her disappearance from Rosewood. Mona asks if she got everything she needed while admiring her clothing, and Ali tells her that she saved her life, and doesn't know how she can thank her. Mona tells her to thank her by staying gone and safe, which makes Alison smile and tell her to come over to the mirror. She makes her look at herself, and tells her key things to get rid of that will make her prettier and more popular. Things such as getting rid of her glasses and knee-socks, seeing the right people at the right places, and tells her that she doesn't have to be a loser anymore. Mona thanks her and smiles. She then notices that the Alison bracelet is on the counter, which she later steals. Later in the same morning, Mona watches as Alison packs her bags into the car and drives away from the Resort.
|“|| Alison: I'm not afraid of you, Mona.|
Mona: You used to be a much better liar.
— Alison and Mona in Miss Me x 100
Mona stands in The Brew watching a television that is delivering news about Alison's disappearance, and the fact that the police believes that Alison is in New York with The Liars. Mona puts her jacket on and looks at an unknown person, stating that Alison's return changes everything.
Mona tells them a group that while they may not know each other, they all have one thing in common - they were all targeted Alison DiLaurentis. She explains her story, saying that while Alison was here she wasn't Mona - she was Loser Mona. This leads to everyone in the room admits their nicknames, with Paige chiming in that it's in the past and she isn't afraid of Alison anymore. Mona tells her that maybe she should be, considering the fact that she's not even back yet and she's already managed to breakup her and Emily, saying that there is no way Ali's going to let them be a couple. Paige asks what it is that she wants them to do, with Mona saying that she wants them to stick together, since the bigger they are the harder Alison will fall. Paige wants to leave, and Mona warns her that she can't protect her if she's not with them, before Melissa Hastings enters telling Mona that they don't have much time.
Mona has heard about Alison and talks to Mike about it, and reveals that she bought whistles for all the girls at the school. She is also going to ask all the principal to let them all download an app on their phone. She later tells Aria that she's surprised that considering what happened to Alison, she shouldn't be walking alone and offers her one of her whistles. Aria then tells Mona that she knows exactly what happened the night that Alison disappeared, and that she knew that Alison was alive the whole time and helped her disappear.
Alison visits her grave in the mausoleum, with a rose in one of her hands. She hears a noise behind her and is surprised to see Mona, and asks if she followed her. She admits that she isn't supposed to be out of her house, but she had to come and see the grave. She assures Mona that the girl that they made the grave for really is gone and she isn't that person anymore. She opens up to Mona about how she understands that Mona hated her and wanted her to go to hell - and going was easy, but coming back is hard. She tells her that she needs her, but Mona responds by quoting a text that she had sent to Alison about New York. She tells he that she did send the text, and should have signed it since she doesn't have to hide anymore - but Alison does. She warns her that she's going to wish she stayed dead.
Whilst getting Hanna and Aria to sign a get well soon card for Ezra Fitz, she asks them what it's going to be like when Alison comes to back to Rosewood High School. The girls look at her confused, and Mona chuckles saying that if Ali is still Ali she's going to want to come back and pick up where she started, and now she has a story to tell. She then hints about knowing that Alison made the whole thing up.
In a flashback, Mona walks up to Hanna who had just finished binging and is staring at Alison's missing poster. Mona mentions that the whole Ali-thing is sad, and the two continue to converse making small talk. Mona mentions that the longer that people are missing the less likely they are to come back, and that Alison looks really pretty in the missing flyer. She then says that if Alison is really gone, someone's going to need to take her place. In a separate flashback, a now skinny, blonder, more Alison-resembling Hanna tries on one of Alison's old tops, despite her not thinking that it will fit. Mona pushes her into trying it on, and Hanna is surprised when it fits.
Later in present day, Hanna confronts Mona about knowing that Alison was alive, and Mona tells her that the point was that she was gone. Hanna angrily accuses Mona of her turning her into Alison - even making her walk, talk, and dress like her. Hanna accuses Mona of here still wanting Alison there even though she was gone, although Mona denies this.
Mona offers Aria and Hanna Shana Fring's old copy of The Scarlet Letter to give to Alison, since Ali will need it to catch-up since she's coming back to Rosewood High. Later, Lucas tries to convince Mona to end her army as he feels bad for Alison, as he believes that she was held capture and that the universe has punished her enough. However, Mona tells her that what they're doing isn't punishment it's just some preventive measures. When Lucas still wants to drop-out as he feels bad for Alison, Mona tells him that Alison really did make the whole abduction story up. That night, Mona confronts Paige who accuses her of becoming just like Alison.
Alison returns to Rosewood High, where she is greeted by a number of students. Mona, joined by Lucas, watches the scene with disgust and disdain.
That night, Alison is walking alone down the street when she notices that a car is following her. She hurries into the church believing that she'll be safe there. Once inside she hears a noise and heads into a smaller room, where she finds the windows clattering. When she turns around she sees Mona standing behind her. She angrily tells her that she doesn't scare her, and Mona snaps back that she's not as good of a liar as she used to be. Disgusted, Alison walks past Mona but stops when she hears Mona say that she knows that Ali and the others were in New York the night Shanna died and she can prove it. Ali turns around to face Mona, asking her what it is that she wants. Mona claims that she's wanted what she's always wanted - for Alison to leave town and stay gone. She doesn't care how she gets there or where she goes, she just wants her gone. She walks closer to Alison as she speaks, and the latter states that she isn't a threat to her anymore. Mona doesn't believe that Alison has really changed, and she may have convinced Hanna and the others of this, but she knows that her attempt to be a decent person won't last long. Ali claims that people do change, but Mona tells her that when someone shows her who they are she believes them - she doesn't need to be taught a lesson twice. Alison asks her what she's suddenly the victim of and brings up her time as A, torturing and bullying the girls. Mona claims that she feels horrible about that but she's better now - even the doctors say so, but Alison doesn't believe her. She states that if Mona could prove that they were in New York she would have done it by now, and warns her that she's back and staying so she'd better get used to it. Mona angrily yells that no one wants her here, but she knows that isn't true. She brings up Cindy and Mindy, and the fact that all she had to do was apologize to them and they were begging her to sit at their lunch table. She claims that it won't take her long to win over her army of losers, and that she made her Loser Mona once before and she can do it again. Overcome with anger, Mona slaps Alison across the face. A moment of silence passes by, before Alison slaps her back hard enough to leave a mark. Mona is shocked and looks at her with a fearful and surprised expression on her face. Another moment passes, before Alison tells her that they don't have to do this if she just leaves her alone, before leaving the church.
Back at Emily's house, she recaps the events to the Liars. When asked what she did when Mona slapped her Ali lies and says that she just stared at her, and appears to be genuinely afraid. She also claims that there is no way that Mona was the person driving the car that was following her, since she couldn't have gotten into the church that fast and suggests that she had help. The Liars decide that it was an ambush, and later admits that she's scared of what Mona might know about New York.
The next day at school Mona is surrounded by her Army when Alison enters the room with the Liars. Mona claims that Alison attacked her last night, and points out the scratch across her face. She then shows them an edited version of the what happened the night before. In the clip, Alison tells her that it won't take her long win over her Army of Losers and tells her that she can make her "Loser Mona" again before slapping her. The Liars are shocked as they now believe that Alison lied to them about what happened, and Alison glares at Mona before shaking her head and leaving the room, heading to the bathroom. The video makes the Liars turn against Alison, as they believe Alison to be a liar and are upset that she lied to them about what really happened when Mona "attacked" her. Alison also states that is the last time that she will ever underestimate Mona.
Paige gets out of the pool when Emily comes up to her demanding Paige to tell her who Mona is working with. Paige says that she can't tell her, especially after the way Alison treated Mona, with Emily revealing that Mona altered the video. Paige still doesn't want to help, as she believes that Alison isn't sorry about the way she treated anybody and she's still the same person she was before. Emily tells her that someone caused the gas leak at the Cavanaugh house, and Paige asks if she really thinks that Mona is behind it. Emily tells her it's possible, especially since Mona has help her friends. Paige wonders why Mona would want to blow up the Cavanaugh house. Emily says that's what they're trying to figure out, and that she's aware how Paige feels about Alison, but asks if she could really live with herself if something bad happened to Alison knowing that she could have stopped it.
Emily talks to Mona outside of the Cavanaugh house, which is being rebuilt after the recent explosion. At the end of the conversation, Mona tells Emily to give her love to Alison before leaving.
Hanna and Mona are in Mona's car, and Hanna tells her that she knows Alison brings out the A in her, which is why she isn't going to trust her. She then states that she plans to get answers about who set-up the Cyrus Petrillo thing (where he is the one that kidnapped Alison), either from Mona or one of her devices. They then watch Alison, Mr. DiLaurentis, and Detective Tanner leave Rosewood Police Department and get into Tanner's car. Hanna wants to follow them, but Mona states that they don't need to, as she has access to Tanner's phone now. Later, Mona admits to Hanna that the reason she went on the offensive with Alison and created her Army is because Ali scares her, and she didn't want to face her alone.
While opening up to Aria after running out of the theater, Mona says that Alison underestimated Aria. She then says that all she's ever tried to do is protect herself from Alison. Aria asks if that's why she built an army, and Mona reveals that it is. However, her army is gone now that Alison has persuaded them away from her with, "candy, a smile and that lilting little laugh". She then warns Aria that when Alison is done with her she'll come after Aria and the others, especially now that she can't trust them anymore - not after Cyrus or New York.
Mona is visited by the Liars who need her help with Alison. Mona asks what she did to them, with Hanna saying that she didn't do anything to them - yet. Aria says that it's what she's about to do, with Emily chiming in that she's at the police station talking to the police. Mona understands that they don't know what she's telling them, and Hanna tells her that they've been lying for Alison ever since the latter came back. Mona wants to know why they can't just ask her, but they don't like that she'll tell them the truth, and they need her help because she's Mona.
Later, Mona is talking to the Liars and says that Alison stole her life from her the moment she crowned her Rosewood's biggest loser. That she was so convincing, that even Mona started to believe it was true. But she can't help them, since she's already on the top of Alison's hit-list and is terrified to think of how far Alison will go to stop her. When questioned about if she's really that scared of Ali, Mona asks if they aren't - and if their fear of Ali is the reason they're here. She then apologizes to the girls for taking out all her "Ali-anger" on them. Mona heads upstairs after saying goodbye to Hanna and the others, and believing Mona to be gone, Mrs. Vanderwaal asks Hanna if now that Alison is back, if the bullying is starting again. Hanna states that she isn't friends with Alison anymore so she doesn't know, but she does know that Mona is afraid of Alison - they all are. Mona hurries into her room and calls someone, telling them to send out a "Code A" and that Alison is planning something big.
Mona heads to the Brew later that night, and is shocked to see that no one is there except Lucas. She asks where everyone is and he tells her that Alison go to them and has everyone convinced that she's the saint, and that Mona is "Crazy Mona". She looks in the mirror with tears in her eyes, and asks if he thinks someone can be crazy without knowing it. Lucas tells her not to think like that, and that if she starts to believe the nickname then Alison wins. Mona then quickly says that she wasn't talking about herself, she was talking about Alison, and she believes that the latter has gone, "full-on socio".
At school the next day, Mona tells the girls that Alison volunteered to take the polygraph test. She tells them that once you believe a lie it becomes the truth, and Hanna believes the only reason that Alison would be lying to herself is if she did something so terrible that she doesn't want to believe that she did it. However, Mona thinks that she's actually playing a game. Aria is confused about why she would take the lie-detector test for fun, but Mona quickly says that she believes that Alison took it because she isn't having fun anymore. That Ali can't play with her dolls (the Liars) anymore and that is how she's ending the game. Mona also tells them that she think Alison stole the A-game from her, and is now A. She goes on to say that Alison assembled the perfect group: smart (Spencer), loyal (Emily), admiring (Hanna), and compassionate (Aria). Aria asks what the perfect group is for, and Spencer realizes that they're the perfect group for a sociopath to manipulate. Mona believes that Alison would have gotten bored with just one of them, but altogether, they're a challenge. Aria admits that she always wondered why Alison picked her, and Mona says that it's because Alison doesn't feel anything, and to be able to mess with someone who feels a lot must be fun. After speaking, Mona tells them that she can find out what Alison told the cops so they can have a chance to get their story straight. She also says that she's helping them because she got early acceptance letters from three-colleges, but needs to survive Senior Year first. She also makes them promise not to tell anyone that she's helping them or the deal is off.
After speaking with her mother, Mona sees Alison on the opposite side of the hall with a group of new girls. She freezes, a fearful expression crossing her face. Alison spots Mona as well and sends her a coy smirk, before she is called to Principal Hackett's office. Alison starts walking down the hallway and walks past Mona, who glances at her worriedly. Alison, however, only has a smirk as she passes Mona and stops at the Principal's office door, sending Mona another smirk before she enters the office. As Mona turn to head down the hallway, she is met with glares and smirks from Alison's new group. She heads to the bathroom, where she hides out in a stall before receiving a text message from Lucas go "go" before hacking in Rosewood P.D.'s server and accessing Alison's files.
After school at Spencer's house, the group and Mona watch Alison's polygraph. They discuss the polygraph after, with Mona saying that the police might think that Spencer killed Bethany. Caleb enters the house and Mona says that she knew Hanna told him so she asked for his help, and he reveals that he accessed more of Ali's files. In the reports, the police now think that Alison had nothing to do with Bethany's murder, and that Spencer killed Bethany to gain favor with Ali. There is also a warrant about to be released for Spencer's arrest, which sends the latter into a frenzy. Mona tells her to relax, and that there has to be something in Bethany's Radley file linking her to Alison. The Liars and Mona agree to help Spencer in any way that they can, especially now that Ali is a free-woman.
That night, after sneaking into Radley with the help of the other Liars, Spencer and Mona learn that Alison may have known Bethany since Mrs. DiLaurentis was having an affair with Bethany's father.
The next day, Mona is going through all of Bethany's Radley files and tapes, trying to find an obvious connection to Alison. She helps Leona load her bags into the car, and says goodbye to her, promising to get on the road after finishing her report. She hears a rustling behind her and looks, but doesn't see anyone and heads into the house locking the door as she looks out the window. She then calls Aria, and tells her that Alison lured Bethany to Rosewood after learning about the affair between Bethany's father and her mother. She was jealous and wanted Bethany dead. Unbeknownst to her, downstairs, a woman with blonde hair dressed as A picks the lock to Mona's front door before entering the house. Once inside, she lowers her hoodie to reveal that she has long blonde hair - a similar shade to that of Alison's. A then walks up the steps calmly, admiring the artwork on the walls. In Mona's room, Mona quickly tells Aria that Alison is A and that she can prove it. After hanging up with Aria, Mona looks in the mirror and says, "game over, Alison. I win." There is a creak behind her, and Mona calls out asking if it's her mom returning home for something she forgot. There is no response, and moments later, her bedroom door opens and A walks in. Mona turns around and is shocked at who she sees, gasping in horror.
All of the Liars arrive at Mona's house to find it completely destroyed inside, with blood everywhere. They run upstairs telling each other to call 911, and scream in absolute horror when they see Mona's bedroom. Later, the girls are standing outside of Mona's house with their significant others, crying and waiting for the police to give them answers. Alison watches from between two police cars, a curious expression on her face as she witnesses the scene. The police walk out and talk to the reporters, telling them that while the investigation is ongoing, they have rule Mona's death a homicide. Although they didn't find a body, the amount of blood inside indicates that Mona's wounds were fatal, and that she was murdered. Leona shatters into tears, while the Liars cry into the significant others. Meanwhile, Alison simply looks around before leaving the scene quietly without anyone seeing her.
With Mona's death still be investigated, the Liars believe that Alison murdered Mona to keep her from telling the Liars something about Bethany Young.
Alison is laying in her bed sleeping, when the lights start to flicker. A loud bang wakes her up, and she jolts upwards just as Jessica DiLaurentis walks in. She tells Alison that "she" has a lot to show her, and that she should pay attention. Later, Alison walks around her house and plays the piano with one hand for a little before walking over to a picture of her mother. She carries it over to the couch, where she falls asleep.
In her dream she hears someone playing the piano which "wakes her up", and looking over she sees herself as a young-girl playing the piano. She looks at the child surprised, and then notices that Mona is standing next to the piano as a ghost. This startles Alison, and Mona tells her that she knows that Ali told her not to leave the house without her face on, but this was the best she could do as a corpse for her ice ball. Alison insists that it isn't real, and Mona smirks looking over at young-Alison and complimenting her on being a good pianist. Alison realizes that the little girl is her, and Mona asks her if she remembers the day but Ali doesn't. Mona says that it isn't pretty, but she has to see it which confuses Alison. Young-Ali hits a key on the piano but it doesn't make a sound, and curious, she peaks into the piano where she discovers two yellow dresses that are identical. Jessica enters and scolds young-Ali for snooping, but the child says that she didn't mean too and thinks that Jessica and Kenneth got her the same dress. Jessica says that there isn't too dresses, and tries to get her to realizes that there is only one dress - getting her to lie about the dress. Young-Ali agrees to lie and recites a lie to Jessica - she looked in the piano and found one yellow dress. Mona looks to Alison and tells her that is the moment the monster that is Alison was born. Ali asks her who the other yellow dress was for, causing Mona to chuckle and tell her, "it won't be that easy, bitch". In that moment, Alison wakes up on her couch moments before a Christmas tree ornament falls from the tree.
At the ice ball, Alison meets up with CeCe Drake, who wishes her a merry Christmas. Alison opens up to CeCe about how her mother came to her in a dream to warn her about Mona, and CeCe assures her that she knows that Mona can't hurt her anymore.
At home, Alison falls asleep again and is awakened inside her dream by Mona singing, "Hark". After she finishses singing, Alison rolls her eyes and Mona asks her how the party was. Alison ignores her, but Mona warns her that ignoring her won't make her go away - it'll just make her angry. She then makes all of the curtains blow despite the windows being closed, which freaks Alison out. Everything is quiet for a moment before Mona jumps out beside her, appearing as she yells, "boo!" which makes Ali jump. She admits that she's afraid and asks if that's what she wanted to hear, and Mona admits that it wasn't as gratifying as she thought it would be. Alison asks what it is she has to say or do to make her go away, and Mona smugly tells her to wait before looking straight again with a smirk. Alison looks and sighs, not wanting to watch, "The Christmas Carol", as she believes it is depressing, and asks Mona if they really have to watch it. Mona tells her that if she's depressed now, to wait until she looks over at the other side of the room. When Alison does, she is shocked to see a casket on the other end of a church that they she is now standing in alone. When she looks in the casket she sees that it is her body, and Mona appears beside her. Alison asks her when she dies, and Mona eerily states that it doesn't really matter, although it does matter to Alison. When Mona tells her that it only matters to her, implying that the empty church means that no one came to her funeral, and then tells Alison that she looks good considering they never found her legs. Another woman, dressed as The Black Widow, appears just as Mona disappears. The woman is Jessica, who tells her that she is sorry and that Alison is going to Hell. After learning this, Ali runs to the locked church doors and bangs on them, screaming no and for Mona. Alison lurches up in her bed, awake, just as Mona slams her hands down on the bed, telling her to wake up and warning her that it's Christmas, and she doesn't wanna miss it.
Three-months has passed since Mona's death, and a funeral is held for her, despite the police not finding a body, a murder weapon, or having arrested anyone. The Liars still believe that Alison killed Mona as she is A, and attempt to reach Alison. Ali walks up to Mrs. Vanderwaal and tells her that she only came to pay her respects, and tell her again that she had nothing to do with Mona's death. Infuriated, Leona slaps Alison and screams at her to tell her where Mona's body is. Shocked, Alison just looks at Leona with a serious look on her face while holding her cheek.
That night, Alison attempts to talk with Aria who only wants nothing to do with her. Alison tries to convince her that she isn't A, but Aria is convinced otherwise. She accuses her of stealing the game from Mona, killing her to cover it up once Mona had proof, and killing Bethany Young because she was jealous of her.
Jason is taken to the police station where he is shown footage of Mona's gruesome murder, via cameras that Mona installed months earlier. On the tape is a blonde dressed as A, throwing Mona around and seriously injuring her. When asked if anything about the blonde seemed familiar, he admits that it could be Alison, which Tanner finds interesting since he told her that Ali was with him all night. He admits to lying about Alison being with him when Mona was killed, incriminating his sister in her murder.
The next morning, Ali finds Jason sitting on the couch looking at pictures. The pair talk, and Ali realizes that Spencer and the others told him about their suspicions of her killing Mona. Jason confronts her about where she really went that night, and the fact that when she did come home she didn't say anything to him. She tells him that she's being framed and that the Liars don't want her there anymore, wish she never came back, and are trying to get rid of her now. She begs him to believe that she didn't kill Mona.
That night, Alison hurries home to find Jason standing in the doorway, just as police sirens start to blare and can be seen through the window. She asks him to try to stall the police, and he looks at her serious before he lets her go past him. Once outside, her path is blocked by the Liars who are convinced now more then ever that Ali killed Mona. She begs them to get out of her path, but they refuse to let her escape and get away with murdering Mona. Ali tells them that she is being framed by A, and that if she's gone no one will be able to protect them and they'll all be next. She then tells them to move and attempts to push through them, but is shoved backwards. Moments later, Linda Tanner tells her to put her hands in the air, before arresting her for the murder of Mona Vanderwaal.
Alison is still in prison for Mona's murder pending her trial. While she was originally in a different prison, she was transferred after being attacked by the other inmates. In a conversation with Toby, she asks him if he remembers what it's like to be in a cage for something he didn't do.
Ali calls Jason from within prison, but since he believes that she killed Mona he refuses to take the call.
Later, she is visited by Hanna, who confronts her about being A and killing Mona. This angers Alison who claims that she doesn't know what she's talking about, and that if she's really as clever as everyone thinks she is, she would have given herself a much better alibi then Jason. Hanna starts to leave, but before she does Alison asks her if she wants to know where she was the night of Mona's murder. She doesn't wait for a response, and tells her that she received a text from Cyrus Petrillo asking to meet up, and feared that he had gone back on their deal. So, she went to the meeting place and waited for hours but he never showed, and when she heard that Mona's was missing she realized that it was all an elaborate trap set by the real A. She couldn't explain that to the police or her father, but he had lied for her anyway.
Toby tries to assure a nervous and scared Spencer that Alison is in jail and can't hurt her, but she reminds him that Ali was able to plant that knife (the presumed murder weapon) in Mona’s backyard from jail. Toby isn't entirely convinced that Alison was the one who planted the knife, but Spencer is convinced that she had someone on the outside help her plant it.
Meanwhile, Jason fills Aria in on Alison’s case. When Aria asks him if their father believes Alison is innocent, he tells her that their father will do anything to protect her - even if he has to lie to do it, and knew what Alison was capable of. Jason reveals that the police have a theory about Alison having help in getting rid of Mona's body. Aria realizes that since Alison passed the lie detector test they administered her about Mona, she must have had help from the inside.
The Bin of Sin - Bonus Scene
Alison is laying in her prison cell after being convicted for the murder of Mona Vanderwaal. She is looking back on her life and how she had everything, and is trying to decide what moment in her life where she was cruel to Mona she would change if she could. If changing one moment could alter history and stop Mona from ever dying or even becoming her enemy.
In a flashback, Alison is walking down the street when Mona happily runs up to her, greeting her by saying her name a few times and smiling. She compliments Alison on her hair, saying that she has been trying for weeks to get her hair to do that for a while now, but it just won't cooperate. Alison rolls her eyes and rudely states that their are cancer patients with better hair then hers, which clearly hurts Mona's feelings. She adds that if she were her - which she's happy she isn't, she would stop trying to be someone she isn't.
In present day, Alison decides that is the moment she would change. If she had a chance to do a do-over and change both of their lives, and questions whether or not she would take it. She contemplates that if she had decided to make another choice that day and actually help Mona, she would have made a friend that day instead of an enemy. And that maybe, she wouldn't have ended up in prison.
In the altered reality that Alison had envisioned, instead of mocking and bullying Mona for her hair, she offered to help her. She told her to trust her and went with her to get her hair curled properly, her makeup done, and proper clothing. As they were leaving a boutique they were seen laughing and getting along.
Alison's defense team is attempting to build a case with the help of Veronica Hastings, in the hopes of getting Alison little-to-no prison time. Veronica tells spencer that while the contents of the barrel they found are still being analyzed, the blood droplets on the floor of the storage until weren't Mona's - they were Alison's.
In a flashback, Hanna and Mona are sleeping in Mona's bed, when Hanna asks Mona if Alison came back after a long time, in disguise, would they be able to recognize her. Mona snaps that even if Alison does come back, no one would recognize her or care about her so Alison would go crazy wind up in Radley forever.
Aria and Mike argue, as she believes that he hurt Mona due to the fact that she found Mona's blood in his room. However, Mike claims that he didn't hurt Mona, and that he really cared about her.
In a flashback, he explains that a few nights before Thanksgiving, he went to Mona’s house to surprise her, but found her draining her own blood. He asked her about it, and she revealed that she had stocked a refrigerator full of her own blood. Mona told Mike that she has been offered a chance to make things right by exposing "A" and bringing them down once and for all. Mona elaborates that she is going to smear the house with her blood, and make Alison look responsible for her death, since "A" wants to see Alison locked up. Mona says that even though she hasn’t been in direct contact with "A", she will find out who it is after she earns their trust. After she fakes her death, she’ll disappear and find out A’s identity, and once she finds out, she’ll come back, resulting in Alison getting acquitted. She can then finally take down "A", the girls will finally be safe, and Mona will be painted as the hero. Although Mike strongly disagrees with the plan, Mona convinces him that she will be safe.
In present day, Mike admits to Aria that he doesn't think that Mona is safe anymore, and they were supposed to meet up a bunch of times but Mona never showed. He admits that he believes that "A" double-crossed Mona and actually killed her and framed Alison. He reveals to Aria that he visited Alison in jail and told her about Mona’s plan in hopes of finding out if she knew anything about "A" Aria asks him why he doesn’t think Alison is "A", and Mike tells her that Alison wasn’t even in town when Mona was killed. That A planned for Cyrus to lure her out of Rosewood, so she wouldn't have a solid alibi for the time of the murder. Realizing that Alison really is innocent, she hurries to her friends to tell them the truth.
Aria fills Spencer, Hanna, and Emily is on what Mike told her. They realize now that Alison is innocent, and they were the ones who got her arrested for Mona's murder in the first place, and that they destroyed any evidence that could have proven Alison is innocent, thus, helping "A" get what it wants. The group decides that they have to try and help Alison before she goes to trial since they accused her, to her face, of being A.
The Liars visit Alison in prison to tell her the truth about Mona's plan, and the fact that Mona planned to frame Alison for her murder and made a plan with A to do it. However, A turned on Mona and killed her, framing Alison for the murder. This upsets Alison, as she can't believe that Mona would really just let her sit in prison and rot for something she didn't even do, but the girls try to convince her that Mona planned to come back and she would be acquitted for the murder charges. Aria tells Alison about her brother's involvement in the plan, and Alison tells Aria that she might have no choice but to tell her lawyers about what Mike knows, as it could be the last thing that could save her. Aria begs her to hold off until they can find A, and Alison reluctantly agrees but will tell them if she doesn't have another choice.
Alison is sitting alone in the Laundry room at a dusty table, waiting for the laundry to be done. She quietly and numbly starts to write letters in the dust with her pointer finger. A guard enters the room asking for "DiLaurentis", and then tells her to follow him. On the table, was Alison wrote is visible - "Mona" in big letters.
She is visited by Veronica Hastings who wants to know why the Liars have been visiting her, and Alison states that they came to see her because they know the truth - that she didn't kill Mona. She also admits that wants to take the stand and tell the jury and the judge her side of the story, but her lawyers won't let her because of all the lies she told and how untrained she is. Veronica agrees with Alison's lawyers and advises her to get a very good coach, with Alison asking her to be the coach.
As she rolls the laundry cart into the laundry room, she notices that there is new writing on the table and is shocked to see what it says. Underneath Mona's name in small letters, are the words, "told everything". That night, as she attempts to fall asleep, a toy barrel is rolled in with a note and Alison doll inside from A. A threatens to kill Alison and put her body in a barrel the same way they allegedly did with Mona.
In a meeting with her lawyer, Rebecca Marcus, the pair are arguing as Alison is still adamant on wanting to take the stand, but Rebecca doesn't think it's a good idea. Rebecca claims that Alison doesn't have anyone to back-up her story, but Alison tells her to contact Cyrus Petrillo, as he had asked her to meet during the time of Mona's murder and set her up. This doesn't change Rebecca's mind, as Alison had already lied about Cyrus kidnapping her and putting Cyrus on the stand might do more harm then good. Worried about her own safety, Alison admits to Rebecca that there is another person who can testify to her being set-up but no where she was at the time of the murder, and Rebecca tells her it's pointless to pull the witness in then. Alison asks what she's supposed to do then, when Rebecca reveals to her that the case has taken a turn as the prosecution is now ready to offer a plea deal. Part of the deal is that Alison will plead guilty to all charges - which Alison doesn't like as she insists she didn't kill Mona - and take responsibility for her actions, name her accomplice, and would then serve fifteen-years in prison. With good behavior, she has a chance of getting out in ten, which upset Alison as she knows that will never happen. She refuses to plead guilty for a murder she didn't commit, and tells her lawyer again that she didn't kill Mona. Rebecca tells her that the evidence against her isn't good, and if it goes to trial then the prosecution will look for life without parole. She also tells Alison that the police is building a case against Hanna Marin, as they believe she helped Alison kill Mona.
In a meeting with Veronica, she tells her that she has decided to take the plea do to being attacked. However, Veronica tries to convince her otherwise, as she doesn't want he to have to live with the terrible lie of naming Hanna - an innocent woman, as her accomplice. Regardless, that night, Hanna is also arrested as an accessory to Mona's murder.
The next day, she meets with Rebecca who tells her that the DA is willing to let her serve her sentence in a minimum security sentence. She hands her the plea on a piece of paper and tells her to look it over and sign it when she's ready. She reminds her that she has to name her accomplice as well. Alison looks down at it, places the pen on the paper and slides it back, saying that she's changed her mind - she won't be taking the plea.
Alison's trial is about to start, and she is being prepped by Rebecca and her father. The next day she sits in the courtroom surrounded by people, watching the jurors walk into the courtroom. The Liars also enter the courtroom and sit on Alison's side to watch the trial. The prosecution leads with a compelling opening statement about Alison bullying Mona in High School, and the defense is about to lie to them jury about Alison being kidnapped and held captive for two-years. The prosecution informs them that Mona knew the truth about Alison lying about her story, and had the power to dismantle the story and ruin the fantasy created by Alison and her "followers". They press to say that is the reason why Alison punished Mona by killing her with a cruel and anonymous dead. Alison sits in absolute shock as she listens to the prosecution, tears in her eyes.
She tells Hanna later on in the prison, that she was communicating with someone through newspapers. They didn't know who really killed her mother, they were just torturing her. She also says that she believes this person was Mona, since the texts ended after Mona was killed.
The next day the table, the prosecution plays the video of Mona being murdered by a blonde for Jason, the jury, and the courtroom. They tell everyone that Jason lied about Alison's whereabouts on the night of Mona's murder, asking why he decided to suddenly the truth. He admits that he doesn't know, but it wasn't something from the video. The prosecution asks if he told the police that the attacker in the video was Alison, and he admits that while he thought the attacker in the video could have been Alison he doesn't believe that now.
Jason visits Alison in prison after the day in prison, and they talk about the trial and what her lawyer thinks. He asks if there is anything he can do, and she suggests he leaves to avoid conflict. He tells her that he believes her - that she didn't kill Mona. She admits to not doing it, but letting a lot of things happen that she shouldn't have.
Lesli Stone takes the stand as the prosecutions surprise witness, which rattles the defense quite a bit. Leslie brings in a postcard that Mona sent to Leslie about her being threatened by Alison, and was having a hard time dealing with it. The threat was that if Mona< "opened her trap about the kidnapping she'd be eaten by worms". When asked why Leslie had taken so long to bring the letter forward, she stated that she couldn't find it. She cries about how she couldn't realize the threat earlier, and didn't take it seriously enough. She lies about how Alison's friends were on guard about anyone touching Mona's things or asking questions when she came to visit. She states that Hanna Marin practically stalked her the whole time she was there, and didn't even let her into Mona's room.
Later, during a call with the Liars and Hanna (who is also in prison but is on another phone that is on speaker), they talk about Leslie suddenly appearing. Alison states that she's never even heard of Leslie Stone before, and Hanna informs her that she was a friend of Mona's from when she went to visit her Grandmothers. Alison is upset that Leslie managed to dig up some letter that made her look like a murderer, and admits that her defense teams doesn't have anything to prove them wrong. She tells the Liars that they have to find something, because she's spend life in prison because Mona wanted to use, "her last Laurel and Hardy stamp". She reveals that someone might have seen her at the park on Thanksgiving, but isn't sure if someone was really there or not, as all she heard was banging and saw a jacket. Before they can continue, their time is up and they are forced to hang up.
Rebecca proves that Alison couldn't have killed Mona, as Mon was hurled and thrown like a rag-doll. Something that Alison isn't capable of doing due to a fractured arm that never healed. However, the prosecution brings up a trophy that she won for archery that pokes holes in this story. Unbeknownst to everyone, Alison and her bunkmate had pre-rigged the targets so that she would win.
Later, the jury is finished deliberating and Alison stands in the courtroom ready to here her fate. The commonwealth has found Alison guilty of murder in the first degree, which means that Alison will spend the rest of her life in prison. Alison breaks down in tears as she is handcuffed by the guard, and the rest of the Liars are arrested as accessories to the murder.
The Liars are abducted on the way to the prison by A, who takes them to their dollhouse, where they wake up in exact replicas of their room. When the doors open they are reunited, and are lead to a living room that looks exactly like the one Alison's house. In the room, a blonde wearing an Alison mask, Ali's yellow top, and clothes from when she went missing, is playing the piano. Hanna mistakes her for Alison at first. The blonde looks over and lowers the mask to reveal to the shock of everyone, a very much alive Mona. Hanna, with relief in her voice, realizes that it is Mona. However, Mona claims that while it's been a long time she hasn't changed that much, and claims that she is Alison.
During tea-time, Spencer asks Mona where they are, but Mona claims that they are in her living room and asks why she's being such an imbecile. She offers Hanna a cookie and makes a snarky - and very much Ali-like comment, about Hanna not gaining all the weight back from one cookie. When Emily claims that they thought she was dead, Mona says that she's grateful for Mrs. Grunwald for saving her that night. Hanna states that she's really happy to see her and calls her Mona, which angers Mona as she believes she's Alison and loathes Mona. Emily tugs on Mona's hair and is shocked to learn that it's real, just dyed to match Alison's. Bells chime, and they follow, "Alison" to another room to play a game.
That night, Mona wakes up all the girls and tells them to follow her. She informs them of a generator that shuts down every night. She reveals the torture that she's had to endure since she's been kidnapped, and asks if her mom is okay. Hanna then realizes that Mona knows she's Mona, and she tells them that A wants her to be Alison, so that's who she is when A is watching. Hanna tells her that there was a trial and Alison was convicted for her murder, which makes Mona smirk a little and scoff.
Meanwhile, Alison is spending life in prison, when she is visited by Peter and Veronica. Alison enters the room in chains, handcuffs on her wrists and feet which are all connected. Peter and Veronica are worried about where the Liars are as they never made it to the prison. Alison is shocked to hear this, and reveals to them the truth about A, and how A killed Jessica and Mona. She also tells them that they never had any proof to prove that A was even real. She begs them to believe her, as she believes that A took them. When asked why she's decided to come forward now, she reveals that she is going to spend the rest of her life in prison and has nothing else to lose.
|“||I'm just glad I could help. I know I owe you. More then just a car ride.||”|
— Mona to Alison in "O Brother, Where Art Thou"
It has been three-weeks since the events of "Welcome to the Dollhouse", and Alison has been released from prison and her guilty verdict is overturned. She holds a press conference outside of her house and asks Andrew Campbell, whom she believes to be A, to release her friends that he is holding captive in the dollhouse. Alison teams-up with Caleb and Ezra to track down A and find the Liars on their own. They are able to find the girls and free them for the Dollhouse, with Alison embracing Mona when she runs out of the Dollhouse. When the police announce that their is another girl in the Dollhouse, Mona, Alison, and Emily stand together and wait. Alison has her arm around Mona, and Mona standing close to Ali.
Mona returns from her trip to Saratoga, and expresses her concerns to Hanna that Alison is planning her revenge against her, considering she sent her to jail. Later, Mona goes to the DiLaurentis house and drops off a letter in the mailbox for Alison. When confronted by Spencer, who saw her put the letter in the mailbox, Mona says that Ali didn't answer her calls so she decided to write her a letter.
The Liars (minus Alison) ask Mona if she saw anyone the night that Alison disappeared that could have been Charles and Mona admits that she didn't. Aria asks if she knows who she was talking to in Radley that stole the game from her, and she admits that half the time she was so drugged that she was hallucinating Alison.
That night, Alison calls Mona and asks her to pick her up from the hotel her father was keeping her at. When Mona pulls up Ali gets in, and thanks her for picking her up, as no one else had answered her phone calls. Mona states that she's just happy she could help, and knows that she owes her more then a car ride, especially after everything she's put her through. Ali starts to dial a number on her phone, and tells Mona that she's calling the police. Mona tells her not too, but Ali does anyway and informs the operator that she knows who A is - her brother Charles DiLaurentis.
After Alison is abducted by A at prom, the Liars discover that Mona is also at the prom dressed as Little Red Riding Hood. She reveals that she's been tracking Alison's phone calls and texts, and that Ali started receiving messages from Charles. She states that Charles has his own cellular network and that the servers are all located in the Carassimi Group. Once at the Carassimi Group, they discover a room filled with futuristic-type technology. Mona turns on a screen and the group watches in shock as they discover that A has Jason and Mr. DiLaurentis drugged and kidnapped. They also watch in shock as CeCe Drake is revealed to be A.
CeCe, now revealed to be Charlotte DiLaurentis, explains how she had accidentally hit Alison over the head that night thinking she was Bethany. This causes Mona to start crying, and when asked what is wrong, Mona reveals that she had been sending Alison threats at the time but never wanted to actually hurt her. However, that night, she was out for a walk and saw a blonde girl dressed exactly like Alison and picked up a shovel. She was so overcome with anger that every bad thing Alison had ever said to or about her came rushing back all at once, and she hit the girl over the head with the shovel. She tearfully admits that if Charlotte hit Alison, that means that she had actually hit and killed Bethany. This surprises the girls, as they didn't think that Mona hated Alison enough to kill her.
Meanwhile, Charlotte reveals that she stole the game from Mona whilst in Radley. She states that Mona was so drugged-up that she thought she was Alison, and told her all about the girls and how happy they were that she (Alison) was gone. This is what sparked Charlotte to start playing the game and torturing the Liars. Mona claims that she doesn't remember saying any of that, or even talking to Charlotte, but at that time the doctors were still adjusting her medication.
Four-years after the events of "Game Over, Charles", Mona returns to Rosewood under the ruse that she is celebrating her twenty-first birthday. She visits Alison at Rosewood High School, and sits in the back of the classroom while she teaches her English class. After the rest of the students leave, Alison notices that Mona is present and makes a comment about her no longer lurking in the shadows. Mona responds by saying that she didn't expecting her of all people to stay in Rosewood, let alone the school. Ali tells her that after Mona ran her out of town with a pitchfork she grew to like the town, and felt limited in her High School experience and wanted to return as she missed it. Mona smirks and stands up holding a small brown box, informs her that she's in town for her twenty-first birthday and thought they could go out for drinks to celebrate. Alison asks where her new college friends are, and Mona tells her that they already threw her a party back at Duke, but it wasn't the same. She asks if she has time for nostalgia, and opens the box to show cupcakes with butter-cream frosting on them. She sets the box on a desk and Ali smiles down at it, and Mona asks if she's heard from the girls and that she invited them back for a reunion but didn't hear back from them. They continue to talk about the girls and their new lives, with Aria writing and reading, Spencer spending time at the White House and redecorating the garden, Hanna hanging out with Mona, and Emily heading to Stanford to visit Paige.
Mona comments that after everything they've been through, she didn't really think she'd make it to twenty-one, which makes Alison smirk. She takes a step forward and drops her voice lower, telling her that she isn't in town to celebrate - she's here about her. She continues by saying that she knows that Mona applied for a Summer job at Welby - in Charlotte's ward, and that even though Dr. Rollins didn't recognize the alias used on the paper, he saw her leave and thought she looked familiar. Together, they blocked Mona's application. Mona admits that she tried to visit Charlotte legit the first time, but the hospital refused to let her in. Ali finds it strange that Mona had to put on scrubs to visit Charlotte, and Mona admits to thinking that it would take a few tries to get her to open up. Alison sharply asks her what it is that she wants, and Mona states that she's seen her social media accounts lately. That Charlotte seems to be getting better - which Alison states is true, but Mona is worried what will happen if Charlotte gets cell phone privileges and what she'll post about her and the girls. Alison angrily tells her that she's spent everyday with her for the last four-years, and that Charlotte has changed.
However, Mona is about to start a very public career and needs to know Charlotte's true intentions. Alison steps closer to her, to where she's standing directly in front of her, and tells her that Charlotte's only intentions are to get better. Mona steps closer to Alison as well, saying that Charlotte was a master at playing the game and that despite Ali trusting her, she doesn't and asks when she'll get to see her. Alison eerily tells her that she can see Charlotte when she gets out - and she knows that her sister will be released, as she's been trying very hard to be better. The two exchange a dirty and sharp glare, before Mona leaves the classroom. After Mona leaves, Alison calls someone on the phone and tells them that Mona was there about Charlotte. Meanwhile, Mona stands outside the door eavesdropping.
It has been five-years since Charlotte DiLaurentis was revealed to be A and admitted to Welby State Psychiatric Hospital. Alison asks the Liars to return to Rosewood and testify that they aren't afraid of Charlotte anymore, so that she can be released. Mona also returns much to Alison's disliking. Alison informs the girls that Mona insisted that she be heard at the hearing, even though Alison tried to block her from speaking. At Charlotte's hearing, Hanna, Spencer, and Emily state that they aren't afraid of Charlotte anymore. Mona originally seems as if she's going to be against Charlotte being released, which scares Alison, but Mona changes her mind last-minute and tells the judge to let Charlotte out. She agrees with everything that Alison has been petitioning the courts for. Due to her statement, and the three-girls' statements, Charlotte was released from Welby and Alison was reunited with her sister. After Charlotte was released, she went missing and her body was later found outside of the bell tower, and her death ruled a homicide. Mona attended Charlotte's funeral, although she did not interact with Alison.
Mona, alongside Toby and Spencer, break into Radley and find Mary Drake's file. They learn that Charlotte was adopted by Kenneth and Jessica, and that she was the biological child of Mary Drake. They also presume that Charlotte hid the file, but Mona states that Mary might have hid the file instead. She also mentions that this means that Alison wasn't Charlotte's sister but her cousin, and this could have given her motive to kill Charlotte.
Mona is sitting in the Hastings household going through a hat with names in it. Everyone had placed a name in the hat of who they thought had killed Charlotte. While some said Mona, Mona herself said that she believed Alison was the killer. They start to discuss the possibility of Alison killing Charlotte, and it becomes clear that not everyone is completely convinced. Emily says that Alison loved Charlotte and stayed in Rosewood to take care of her, then asks why she'd do that just to kill her after she got out - that there is no motive. Toby says that she's been on her best behavior since she got back, but they can't pretend that the Alison who blinded Jenna never existed. Mona chimes in and states that it's possible that Alison's goody-two-shoes act go to be too much for her to handle and she snapped, killing Charlotte.
Alison, Spencer, Caleb, Hanna, and Emily discuss the possibility of Mona being A.D. Spencer states that they need Mona if she's really A.D., and Alison questions this, not understanding why they need Mona and why they can't just let Tanner arrest her. She gets visibly annoyed when Spencer states that they need Mona to tell the police what's been happening.
Later on, the girls gather together at the Lost Woods Resort after learning that Mona tried to kill Hanna that night, and did kill Charlotte. Ezra suggests turning her over to the police, which Spencer shoots down. However, Alison quickly states that Mona killed Charlotte and tried to kill Hanna, but Hanna states that Mona didn't even know it was her. Ali looks over at Mona and questions why she is dressed like she was in High School, and Spencer states that Mona went back to a safe place after she killed Charlotte. A place before everything went wrong and all she had to deal with what Alison picking on her at school, which makes Alison avert her eyes.
After the Liars are released from all charges dealing with Archer Dunhill's murder, they go back to the Lost Woods. Alison stands off to the side and listens to the story of how Mona killed Charlotte in self-defense, after the two engaged in a serious fight. In the morning, the game ends after Mona admits to killing Charlotte and Mary confessed to killing Archer, and Mona is admitted to Welby to receive treatment.
A year has passed since Mona was revealed to be Charlotte's killer, and Mona has just been released from Welby State Psychiatric Hospital. Later, Mona spies on Alison and the other Liars for A.D.. That night, Hanna brings Mona along to Aria's rehearsal dinner, only to be met by an angry Alison who asks Hanna if she's nuts. Hanna explains that she didn't have a choice and asks the girls to be cordial and fake their politeness for one night, to which they all agree to. Later, Mona and Alison are seen together when the Liars alongside Caleb and Toby search for a kidnapped Spencer, and when an unknown cop arrests Alex. At the end of the episode, Mona is seen in France owning a doll-shop. In the basement, she has created her own dollhouse with Alex and Mary as her dolls.
Alison (to the Liars in front of Mona): If you ignore it, it will go away.
[Alison about Mona in a flashback]
Alison: Do I know you?
Mona: No. But you will.
[Alison and Mona at the Halloween party in a flashback]
Alison: Okay, what do you think Loser Mona was doing in there? Praying for bigger boobs?
[Alison to Spencer about Mona being in church in a flashback]
Mona: Hi Alison! I really like your hair. I've been trying to get my hair like that but... It just won't cooperate.
Alison: Mona. There are cancer patients with better hair. If I were you - and I'm happy that I'm not, I would stop trying.
[Alison and Mona in a flashback]
Alison (softly): Crap.
Mona: I can't believe you're here! It's kind of like we're shopping together! (pause) Alison?
Mona: Why are you dressed like that? What's going on? (gasp) Is this some sort of a game?
Alison: Mona. Can I tell you a secret?
Mona: For real?
Alison: It's for real. And for keeps.
Mona: I can't believe you're talking to me!
Alison: Yeah, well. I'm watching someone.
[Mona looks out the window; Alison pushes her back]
Alison: Mona. This isn't a game. Just... Pretend like you don't know me and take off. Okay?
Mona: Wow. The Ali D. needs something from Mona Vanderwaal. What's it worth to you?
Alison: What do you want?
Mona: To be popular.
[Mona and Alison in a flashback]
Mona: I'm scared for you, Alison.
Alison: I'm scared for me too.
[Mona and Alison in a flashback]
Mona: Maybe you should die.
Mona: Let A think you're dead.
Alison: How do I do that?
Mona: You disappear. You should rest. Come one, I got you.
[Alison lays back on the bed]
Mona: Shh... Everything's going to work out exactly the way it's supposed to. You'll see. I'll take care of you.
[Mona kisses Alison on the forehead]
[Mona and Alison in a flashback to the night of Ali's disappearance]
Alison: You saved my life, Mona. I don't know how I can thank you.
Mona: Thank me by staying gone. And staying safe.
Alison: Look at yourself. Ditch the glasses and the barrettes, have Kim at the salon do your hair and ask for Sydney at the makeup counter. Buy everything she tells you too, and never go to school without your face on. Now, burn those knee-socks, tell Manny at the boutique that Vivian sent you. You don't have to be a loser, Mona.
Mona: Thanks, Ali.
[Mona and Alison in a flashback]
Mona: I am so over Ali, I told you. She was never my friend - but Hanna was.
Mona: Did anyone see her?
Emily: See who?
Mona: Alison. She pulled me out of there she pulled us all out.
Aria: No, you're hallucinating.
Mona: She was here, I swear it.
Mona: Alison stole my life from me when she crowned me Rosewood's biggest loser. And she was so convincing, that even I started to believe her.
Alison: Did you follow me? I'm not supposed to be out of my house. But I had to come here to see it all. The girl they made that for... She really is gone. I can't be that person anymore, Mona. I know you hated me, you wanted me to go straight to Hell. Going there was easy, it's the coming back that's hard. But you and me we... We understand each other. I need you Mona. As a friend.
Mona: "The truth will bury you in a New York minute." In case you were wondering, that was me. I sent that text. I guess I should have signed my name because... I don't have to pretend to be anyone else anymore. I don't have to hide. You do. And you're gonna wish you stayed dead.
Paige (to Mona about Alison): Mona. I'm just curious... Do you ever wonder when you became the very thing you're afraid of?
Alison: I'm not afraid of you, Mona.
Mona: You used to be a much better liar.
Alison: What do you want, Mona?
Mona: What I've always wanted. And that's for you to leave town. I don't care where you go or how you get there, I want you gone.
Alison: I'm not a threat to you.
Alison: You're suddenly the victim of what, Mona? My bullying? What do you call what you did to those girls? You almost killed Hanna.
Mona: No one feels worse about that than I do. But-but I'm all better now. Even the doctors say so.
Alison: I don't believe you. If you could prove that we were in New York, you would have done it already. I'm back and I'm staying, so get used to it.
Mona: No one wants you here!
Alison: You're wrong, Mona. Just like before, everyone wants to be my friend, and that's what you're afraid of. All I had to do was say I'm sorry to Cindy and Mindy and they were practically begging me to sit at their lunch table. You're scared because you know that it's not gonna take me long to win over your army of losers. I made you Loser Mona once, and you know I can do it again.
[Mona slap Alison, who slaps her back]
Alison (about Mona): That is the last time I underestimate that bitch.
Mona (to Emily): Give my love to Alison.
Mona (to Hanna): Why do you think I went on the offensive? She scares me to death. I just... Didn't wanna face her alone.
Mona: I'm just trying to protect myself. That's all I've ever been doing. Protect myself from her.
Aria: Is that why you built an army?
Mona: It's hard to keep the troops in line with Alison offers them candy, and a smile, and that lolting little laugh. And maybe you won't believe this, but I'll say it anyway. When she finishes with me she'll come after you, and the others. She can't trust you anymore. Not after Cyrus and... Not after New York.
Mona: Game over, Alison. I win.
[Mona to herself about Alison]
Mona (as a "ghost"): I know you told me never to leave the house without my face on, but as a corpse, this is the best I can do for your ice ball.
Alison: This isn't real.
["Ghost" Mona greets Alison in her dream]
Mona (as a "ghost"): Wake up, bitch! It's Christmas, and I promise, you don't wanna miss it.
Alison (to Jason): I'm being framed, Jason. Spencer, Emily, Aria, Hanna... They're all working together. They wish I never came home and now they want me gone. You have to believe me, I did not kill Mona!
Carla Grunwald (to Hanna about Monison): Each one hated the other, because each one feared the other, because each one knew something about the other.
Linda Tanner (to Alison): Alison DiLaurentis, you are under arrest for the murder of Mona Vanderwaal.
Alison: Have you ever wanted a do-over? I always thought do-overs were for losers. Losers made tragic choices about their hair, clothes, boys. Well, I had everything figured out. But lately, I've had a lot of time to think. What if... What would I do-over if I could? Would a second chance change history? That's it. That's the moment I would change. But it's easy to say you would do something different. If I had the chance to do a do-over... To change both of our lives, would I take it? If I had made another choice that day, maybe Mona's fate would have been different. Maybe I wouldn't have ended up... Here. Maybe I could have made a friend... Instead of an enemy.
Mona (as Alison): You guys. It's me - Alison.
[Mona to liars in the Dollhouse]
Mona: I'm scared about what Alison will do to retaliate for me framing her for murder!
Mona (about her time at Radley): I mean, half the time I thought I was being haunted by Ali, the other half of the time I thought I was auditioning for American Idol.
Alison (to Mona): Thank you for coming. You're the only one who answered my call.
Mona (to Alison): I'm just... Glad I could help. I know I owe you more then just a car ride.
Mona: I killed Bethany. I had been sending Ali threats I didn't want to hurt her I just wanted to scare her. But that night, so many people were mad at Alison. She was all alone in her yard and the shovel was right there... It all happened so fast.
Emily: You hated Ali that much? Enough to kill her?
Mona: When I hit her... All I could hear was Ali berating me, every awful thing she'd ever said to me at all once. But if CeCe hit Ali... Bethany had blonde hair and she was dressed just like Alison. I killed an innocent person.
[Mona admits to wanting Alison dead and killing Bethany]
Alison: Mona. And I thought you were done lurking in the shadows.
Mona: Alison DiLaurentis. Never thought you'd be the one to stick around Rosewood.
Alison: After you ran me out with a pitchfork I actually came to like this place.
Mona: And a teacher even.
Alison: Considering my limited High School experience I have to say I missed it.
Mona: Well, I'm in town for my 21st and I thought we could go out for a drink and celebrate.
Alison: What about your college friends?
Mona: Well, they threw me a party at uh, Duke but it wasn't the same. Come on, don't you have five-minutes for some nostalgia and a little bit of butter-cream frosting?
[Mona and Alison in a special-clip during the time-jump]
Mona: You know, Ali, considering everything we've been through I never thought I'd make it too twenty-one.
Alison: You're not here to celebrate. You're here about her. You applied for a Summer job at Welby - and in Charlotte's ward, no less. It's kind of an interesting choice for a poly-sy major. And Mina Davis - creative. Isn't that your mothers maiden name? Dr. Rollins didn't recognize your name on the application but saw you leave. Thought you looked familiar. We blocked your application.
Mona: I tried to visit Charlotte legit the first time and the hospital wouldn't let me in.
Alison: You needed to put on scrubs for a visit?
Mona: I didn't expect to get much out of her in one rendezvous. Figured it might take a few.
Alison: What do you want?
Mona: I saw you've been posting on social. Seems like she's getting better.
Alison: She is.
Mona: Should Charlotte ever get cell-phone privileges what's she going to post? About us?
Alison: I've spent every day with her for the last four-years. She's changed.
Mona: I'm about to start a career in the public eye, I need to know her intentions.
Alison: Her intentions... Are to get well.
Mona: She was a master at playing the game. Even better then me. You may trust her, but I don't think I ever could. When can I see her?
Alison: When she gets out. And I know she will. Charlotte's been working very hard.
[Mona and Alison in a special-clip during the time-jump]
Alison: Why is she dressed like that?
Spencer: She went back to a safe place. You know, a place before everything went wrong where the worst she had to worry about was you being mean to her in the cafeteria.
- Alison bullied Mona throughout High School, and nicknamed her, Loser Mona.
- Mona started sending Alison threatening messages under the alias of "A", to punish Ali for bullying her.
- Mona wanted to kill Alison the night of her disappearance, and even hit whom she believed was Alison with a shovel. However, this was really Bethany Young.
- Mona became A to punish the Liars for being friends with Alison.
- After Ali returned to Rosewood, Mona started a group with Ali's former victims to keep her from returning to power in the school and eventually force her out of Rosewood altogether.
- Mona turned Hanna Marin into the "new Alison", as she still wanted Alison around despite her being gone.
- In order to get in and out of Radley, Mona faked a nurse ID and used the alias "Ali Dee", a direct mention to Alison. Mona even called Alison, "Ali D." in a flashback during "UnmAsked".
- Mona falsified a video to get the school and the Liars to turn against Alison and see herself as the victim - she succeeded in doing so.
- Alison once vowed to never underestimate Mona ever again.
- After Mona's death, Alison was haunted by Mona's "spirit", which showed her the past and future. This was later to be actually Alison's own guilt about Mona's believed death.
- Mona framed Alison for her (faked) death, and Alison was sentenced to life in prison because of it. She was later released after Mona was revealed to be alive and held captive by the new A.
- Alison was in prison for Mona's murder from "Through a Glass, Darkly" to "Welcome to the Dollhouse".
- In a deleted scene, while in prison, Alison changed a scenario in her mind where she was nice to Mona instead of cruel, and the two became friends.
- Mona was forced to dress like Alison and pretend to be her while held captive in A's Dollhouse.
- Alison helped the police (along with Toby and Caleb) find Mona and the other Liars and rescue them from the Dollhouse.
- Mona wanted to kill Alison the night the latter went missing, but instead of killing Alison she killed Bethany Young, who she had mistaken for Alison.
- Mona hallucinated Alison while she was in Radley, and thought that she was talking to Alison when she was really talking to Charlotte (or Hanna).
- Mona killed Alison's adoptive sister and biological cousin, Charlotte DiLaurentis, in self-defense.
- At the end of PLL, Mona had successfully kidnapped Alison's Aunt, Mary Drake and cousin, Alex Drake, and was holding them captive in France.
- Mona and Alison will be main characters together in the Pretty Little Liars spin-off, Pretty Little Liars: The Perfectionists.
- The actresses who play Mona and Alison, Janel Parrish and Sasha Pieterse, are good friends off-screen.