|“||I really loved you once and I really was your friend.||”|
After Alison's disappearance, the four girls (Spencer, Hanna, Aria and Emily) grew apart, and Hanna grew closer to Mona, as they had many common interests. They both loved vogue, they both wanted to be popular and together they gave themselves full makeovers and became the 'it' girls of the school. They love to go to the mall and shoplift. In the season 2 finale, It is revealed that Mona is the elusive A tormenting the girls. However the two of them started up their friendship again.
In the Pilot, Mona is first seen with Hanna shopping in the mall. They comment on each other's accessories before Hanna Marin goes to talk to Spencer. Mona meets up with Hanna after shoplifting a scarf. Mona is then seen with Hanna in class. Emily tells Aria that she and Hanna are the new Queen Bees. Aria comments that she didn't even recognize Mona.
In The Jenna Thing, Hanna and Mona hang out and chat near their lockers after Aria comes out of Ezra classroom, until Mona catches sight of Sean, and Hanna tells her friend that she will see her later.
A few moments after the bell rings for English class, Mona saunters in, asking whether she's late, cluelessly calling Mr. Fitz, "Mr. Fritz" to everybody's amusement. Mr. Fitz then gives the class an in-class writing assignment to complete. Next, Aria hurries in, dropping the "transfer declined" form on his desk while avoiding eye contact with him for as long as she can.Later, Mona and Hanna are walking out of the mall, flanked with plenty of shopping bags. The two girls are happily chatting about the day's finds when suddenly they catch sight of Darren, standing in the parking lot. Mona reassures her friend that he has nothing on her, as she purchased everything legally. Hanna agrees and walks over to Darren to tell him to back off .
In To Kill a Mocking Girl, at school, Mona and Hanna discuss their recent shoplifts, when Sean and Noel walk over. They announce Noel's blowout cabin party planned for the next night. After they leave, Mona questions Hanna about when she is going to have sex with Sean, and Hanna reacts frustrated.Mona states that she isn't pushing for Hanna to do it, but wonders if the relationship is real if they haven't done it. Mona is later seen at the party flirting with a guy, while wondering what is up with Sean and Hanna. Later she sees Hanna marching angrily across the lawn to get to Sean's car. Mona tries asking Hanna what is wrong and why she is taking Sean's car, but Hanna never even responds, instead driving off with the car.In There's No Place Like Homecoming, Mona sits down to talk with the four girls, while insulting Spencer's date, which is the opposite of what Spencer wants people to think of Alex. At Homecoming, Mona and Hanna talk as they insult what other girls look like. Mona and Hanna get into a heated argument when Mona makes nasty comments to Lucas, who has come to photograph the dance for the yearbook. Hanna greets him warmly, but Mona shoos him away. After he leaves, the two argue over whether popularity is more important than befriending nerds, in which Mona warns Hanna that she will not go back to being a loser and will lose her friendship with Hanna if it comes to it.
During The Perfect Storm, Mona sees Lucas and Hanna talking together. Mona is not enthusiastic about this new development and mercilessly taunts Lucas, calling him "hermie" and "shim," names had Alison made up. Mona continues to make fun of Lucas until Hanna tells her she knows Mona's new handbag was purchased on eBay. Mona pretends she bought it as "a goof." Later, fed up, Hanna pulls Mona aside and calls her a hypocrite for treating someone of lesser social status so heartlessly when they used to be on that same strata themselves! Lucas later thanks Hanna for talking to Mona, as she no longer taunted him after Hanna said something.
In the episode "Keep Your Friends Close," Mona is throwing a birthday party for herself, which she calls "Camp Mona" and gives select invites to her friends, including Hanna and the rest of the Liars, as they are her BFF's friends. The rest of the Liars aren't interested, though Hanna tries to persuade them to come and that Mona has redeeming qualities, but they do not change their minds. This changes, though, when "A" tells the Liars that information will be revealed at Mona's birthday party. Then, Mona hears a rumor (thanks to a text from "A") that Hanna lost weight thanks to a liposuction. Mona breaks off their friendship due to anger, going as far as to dis-invite Hanna from her birthday party. She also dis-invites her because Hanna refused to ditch school with Mona, despite Hanna's mother giving Hanna plenty of cash to spend on Mona. So, ironically, Spencer, Aria, and Emily attend Camp Mona without Hanna. Camp Mona turns out to be an over-the-top bash, complete with massage deck, food tents, makeshift hair parlor, and matching T-shirts for all attendees. Her gift table is piled high with presents.
In "Moments Later," when Hanna is hospitalized due to her run in with "A" at the end of the party, Mona visits her in the hospital and apologized, realizing that she was mad at Hanna for a stupid reason. Hanna gladly accepts her apology and they become BFFs once again. While visiting Hanna, Mona told Hanna the reason she chose her to be her best friend. At a party, chubby Hanna vomited while on the trampoline. When she realized everyone was laughing at her she bowed, no longer affected by peoples remarks. Mona found that to be a life lesson. Mona believed that if Hanna could get over people teasing and ignore it, so could she.
In Salt Meets Wound, Mona throws a surprise "Welcome Back!" party when she was released from the hospital. Mona and Hanna are still BFFs but not like before. Their friendship isn't as strong, due to the fact that Hanna's relationships with her former BFFs, are growing once again.
In "Monsters in the End," Mona is worried about Hanna's breakup with Caleb, and states she takes the blame, knowing she should have stopped him from getting to close to her friend. At the Festival she is helping Hanna with a booth and Caleb suddenly shows up. Hanna hides and Mona talks to him, while taking a letter from him to give to Hanna, which expresses his love for her. She reads and promptly destroys the letter, due to feeling need to protect Hanna from being hurt again. Hanna does not find about this until later and thinks even more badly of Caleb as a result.
In "It's Alive," when Hanna finds out from Caleb that Mona never forwarded Caleb's goodbye letter to her, but instead lied, leading her on to believe Caleb was worse than he actually was, she is distressed and angry with Mona and Caleb. Noel Kahn returns to school in the same episode, and Mona begins dating him, to Hanna's surprise. Hanna is angry with her friend for lying to her, but agrees not to judge her for dating Noel. Eventually, Hanna confronts Mona later in the episode, just before her date with Noel. When Hanna leaves, Noel detects something wrong, and Mona just sulks.
In "The Goodbye Look," when the Pretty Little Liars' parents have placed a ban on them hanging out together, the girls sit at different lunch tables. Mona tries to invite Hanna to sit with her, but Hanna is still too sore at her to be her friend again, so all five girls sit at separate lunch tables, eating alone.
Hanna and Mona eventually rekindle their friendship; Mona calls it spiritual. They agree to keep their romantic lives (i.e. Caleb and Noel) out of discussion for the time being, while their friendship repairs, in order to avoid more arguments. However, Hanna does find out why Mona is dating Noel: "He has bad-boy cred now too." (Because of his suspension).In "Touched by an 'A'-ngel," Mona accompanies Hanna in blowing off school to try on her bridesmaid dress for Isabel's wedding. Before meeting her, Mona had formed a negative opinion of Kate, based on what she considered a hideously ugly gown. However, when she meets Kate, she immediately takes a liking to her style. When Kate invites Mona and Hanna to lunch, Mona accepts, while Hanna declines, frustrating Hanna. She accompanies Hanna on a trip to a horse farm, due to Mona's pretending she went to equestrian camp in order to fit in with Kate and her friends. At the farm, they meet Kate's friends. Hanna displays her ignorance about certain cultural references that Kate and her friends make, so Mona cuts in, laughing off Hanna's remarks, trying to save her friend’s face. Later Mona and Hanna are walking through some random woods, their faces stained with dirt. The girls had managed to lose Kate's horses. Hanna gets Mona to admit that equestrian camp had never happened. Hanna snaps at Mona, accusing her of befriending Kate for selfish reasons, and Mona counters that Hanna has been bad tempered ever since Caleb left. Hanna later apologizes.
After returning to the stable, Hanna expresses to Mona her feelings that Kate and her friends were nasty towards her and also considered Hanna clueless. Mona suggests that Hanna wasn't trying hard enough, making Hanna really rail against her future step family and Kate's friends, writing them all off to hell. It turns out that Kate and her friends outside the stable could overhear the whole exchange after Hanna accidentally set her riding helmet on the loudspeaker switch. The girls rush out to undo the damage, but Kate walks away miffed, with her friends at her heels. Mona does seem sincerely apologetic about her mistake and the fallout Hanna has with Kate and her friends.
Later in "I Must Confess," the girls tell Dr. Sullivan about A. That day, Dr. Sullivan attends the school in an assembly to talk about bullying, and about people threatening you. Mona is seen during Dr. Sullivan's assembly on cyber-bullying and rolls her eyes at Hanna, mouthing the word "boring." Ironically, Mona is "A", and probably cared a lot more about what Dr. Sullivan was saying.
In school in "Let the Water Hold Me Down," Mona expresses her worry to Hanna that she is losing Noel. Apparently, he spent most of the previous night on the phone, and she had to convince him to go skinny dipping just to get his attention. As Mona walks with Hanna in the school hallways, they see a student taking down Hanna's homecoming picture; Mona barks at him in her friend's defense. When she continues speaking, Hanna is completely inattentive (thinking about Lucas being missing). Mona is hurt by her friend's insensitivity, and Hanna rushes to a bathroom stall, leaving her pal behind.
In "The Blond Leading the Blind," Hanna tries to console Mona over her break-up with Noel, but Mona is still upset with Hanna. Mona grabs a necklace out of her locker and tries to return it to Noel, who is standing nearby. He promptly dumps it in the trash and laughs when Mona begins to cry. Hanna follows a tearful Mona into the bathroom and tries to comfort her, though she can't seem to find the right words. They agree to use their fake IDs at Rive Gauche later that night. But, when they get there, Hanna and Mona spot Jenna and Noel sitting together in Rive Gauche.
In "Breaking The Code," Mona tells Hanna about going to the mall, which Hanna forgets, but promises that they will hang out the next day at Hannah's house. When Mona receives a text from someone, Hanna asks who it is from and Mona lies. After Hanna leaves, it is revealed that the text is from none other than "A." While hanging out in Hanna's bedroom to pick out clothes as promised, Hanna is again inattentive to her friend, paying more attention to her phone, until Mona receives another message from "A" and tells Hanna about it. She says that it had been happening for a few days and that the messages have been accusing her of shoplifting things. Hanna asks if any of the texts are about her, and Mona replies that there are more about Hanna's mom. She shows her a suggestive photo of Ashley and Officer Wilden. Hanna lies and says it's obviously photoshopped, to which Mona agrees. When Hanna questions what Mona would do with the picture if the mystery texter started threatening her, Mona replies that if she can live through Alison, she can survive this anonymous texting.
Later, Mona visits Hanna's house again and shows Hanna an incident report from when Hanna shoplifted the sunglasses. The report was put into Mona's mailbox by "A." "A" had ordered Mona to give the incident report and the picture to the Rosewood Observer or else she'd be filling out a police report herself. Hanna tells Mona about "A" and that the threat isn't a joke. When Mona asks about what A did, Hanna does not reply properly. When Mona wants to know what to do about the report, Hanna isn't sure but promises she will think of something in time. Mona asks her to hurry, showing the text she got from "A" which says that she only had until 10 am the next day.
The next day, at 10:15 AM, Hanna, believing that Mona turned her mom in, goes to tell Mona that she doesn't blame her. Mona reveals that she went to the jewellery store and returned the necklace she stole. The store owners called the police and it ended with Mona's mom working it out so Mona would just be serving food to the homeless. Hanna thanks her and Mona replies that she wouldn't do anything that would hurt her best friend.
At school, when Hanna passes by Mona's table, she shows Hanna another A message on an apple. Freaked out about it, she decides to take the rest of the day off because she doesn't want to be a sitting target. However Hanna invites Mona to sit with her, Aria,and Emily. Mona was reluctant first, feeling that they won't accept her, but eventually agrees sit together with them.
In "UnmAsked," Mona attends the Rosewood Masquerade Ball with the other girls and later goes with Spencer to the Lost Woods hotel, after Spencer deduces that "A" had rented the room next to the one Alison was staying in. In the room, they find sketches of a Black Swan costume and conclude that "A" must be wearing it at the ball. Mona offers Spencer a stick of gum, but Spencer turns her down. While going through "A's" belongings, Spencer locates a gum wrapper from the same brand of gum Mona just offered her. She tells Mona that she changed her mind and that she'd like a stick of gum after all. Mona agrees, but says she doesn't have any more on her, but that she can go get some out of her car while she goes to call Hanna. She leaves the hotel room while Spencer continues to search. A few minutes later, Mona returns to the room and angrily says "I found the gum!" Spencer looks up from the book and says "You didn't call Hanna...because you're A." Spencer turns around and we see Mona wearing a black hoodie. Mona admits she's "A" and congratulates Spencer on figuring it out, right before knocking her out.
Spencer wakes up in a car with Mona driving recklessly towards Lookout Point. Mona says that she wants Spencer to join the A-team. Spencer asks if the reason Mona became A was her anger at them for letting Alison bully her. Mona laughs and says that she got over that a long time ago. Mona reveals that she became A because she hated them for stealing Hanna's friendship away from her. Spencer pleads with Mona to stop, encouraging her that Hanna is still her friend. As they drive, Spencer is secretly recording their conversation on her phone and sending the video to Aria's phone. Aria, Hanna, and Emily leave the ball immediately and drive to Lookout Point. When they show up, Spencer and Mona struggle, resulting in Mona falling off the edge. Spencer reaches out, trying to save her, but fails. Mona survives and is taken to Radley for psychological treatment. Hanna can't believe that her so-called BFF would do such a thing to her.
In "It Happened 'That Night'", we find Hanna has been visiting Mona in the Radley Sanitarium, and that Wren Kingston is working as one of her doctors. Hanna shows up for answers, wanting to know what she did to make Mona hate her so much. Each time Mona just sits their still and almost lifeless. She has a glazed look in her eyes and remains with a stoic expression. After Hanna leaves, Mona spies as Wren and Hanna speak about her. Later when Wren calls Hanna he states that Mona is making progress and he thinks because it's from Hanna's visits. At the end of the episode Hanna tries to get through to Mona again, and asks her if she wants her to keep coming back. Mona looks over and smiles. Hanna thinks that she is smiling at her, but then realizes she is smiling at an empty chair. Mona is actually hallucinating and sees Alison holding her "Lolita" book, wearing a red coat, smiling back.
Hanna gives Mona a beauty makeover.In "Blood Is The New Black", Hanna is still seeing Mona, who is still catatonic, no matter how many times Hanna mentions new spring colors or Noel Kahn. Hanna gets frustrated this time and yells at Mona about how she feels about her ruining her life. She brings up how Mona would be in jail if she confessed about her hitting her with a car and pleads to know what she has done to make her hate her; she even throws a chair across the room. Mona just stays quiet. Wren explains to Hanna what she's suffering is ambiguous loss - the person she cares about is still there, but she's lost them anyway. Hanna finally figures out a way to break through to Mona - giving her a makeover, complete with eye shadow, foundation, and mascara. Mona looks indifferently at her reflection in the mirror. Hanna gets mad again and says "Look, I didn't come here to play beauty shop with you." Mona speaks for the first time since Hanna's visits - "You're getting them again, aren't you? The texts?" Before Hanna can get anything out of Mona, she's shuffled out of the room. Alone in her seat, Mona slides tweezers out from under her and pricks her finger with it, allowing a drop of blood to bloom.
In "Kingdom of the Blind," Hanna visits again. She is now talking much more and somewhat bubbly. She goes on talking about new pills, water, and gum in a somewhat delusional way. Mona also mentions her parents had come to visit her but they just stare at her like they don't know who she is anymore. She acts clueless when Hanna mentions the new "A," and bluntly asks "Have they found what's left of Alison?"
In "Crazy," Mona gives the liars Maya's website, which eventually tracks them to Nate and the fact that he killed Maya. Hanna thought that Mona did this because she wanted to help them.In "Stolen Kisses," the hospital thinks that Mona has been slipping some of her meds to a visitor. They decide to move her to a maximum-security facility in Saratoga, New York. Realizing that the girls' chances to get more answers about "A" are getting smaller, Hanna approaches Wren about convincing the hospital board to let Mona stay. Wren tells Hanna that he can't do anything about it, so Hanna gives her own formal speech to the board. However, Hanna throws her speech aside and speaks out as Mona's friend to the board. They decide to let her stay.
In "She's Better Now," Mona is released from Radley. Being forced to go back to Rosewood High by her parents, she visits Hanna and pleads for forgiveness. At school people make fun of her and avoid her, with only Jason having a good attitude towards her. Then, with the creepy Janitor on the loose, Caleb uncovers a secret...Mona was never forced to go back to Radley, in fact, she begged to return. Soon after she gained back a minor amount of popularity with a crying out video. She is shown looking at Meredith towards the end of episode...who ends up falling into an "A" trap.
The two make no interactions until the season 3 finale, A Dangerous Game, when Mona is trapped into the fire with the other girls sans Spencer. Mona admits that she has no idea who Red Coat is, and even seemed to be afraid of her. Red Coat then saves the girls + Mona from the fire, with Mona, Hanna and Spencer saying that they saw Alison in the Red Coat. While driving back to Rosewood, Mona admits to the liars that while in Radley, Red Coat approached her for partnership, but conned her into giving her control of the A-Team. Mona says that she was with Red Coat "That Night" with Emily, but she couldn't see a face because Red Coat was wearing a mask.
At the end of the episode, Mona and the liars find Wilden's car, which was apparently fished from the lake. After seeing the video of Ashley running over Wilden, they then see Jenna and Shana help Wilden walk away from the scene. Immediately, Aria, Emily, Spencer, Hanna and Mona all get a text from A at the same time: "You're mine now! Kisses. -A, before opening the trunk of Wilden's car and gasping in shock. It is confirmed that Mona will become A's new victim in season 4, meaning that Manna may once again be reunited.
It has been confirmed that Mona will become A's new target, due to her sloppy work as an A-Team member (her soft spot for Hanna, giving the liars Maya's website, etc...). This indicates that Hanna will reconcile with Mona eventually.
In an aboutface from last season, Mona quickly removes the harddrive from Wilden's dashcam, as police sirens blare towards their location, in what appears to be an act of kindness. The express reason Mona gave was merely to save Hanna's Mom, though, one cannot doubt her motives. She furthers her apparently altruistic acts at the end of the season premiere, when she hands the harddrive over for Hanna to keep, as an act of goodwill.Hanna discovers in the season premiere that Mona was dressed as the Phantom of the Opera on the Halloween Train after finding the mask in the RV. Mona answers her slyly, "To think, we were this close to our first kiss." It becomes further implied that perhaps Mona felt more than friendship for Hanna, when Hanna asks if she wants to go shopping and Mona replies, "C'est un rendez-vous. It's a date." Later in the episode, as they get back from the stores, she confesses, "I really loved you once, and I really was your friend." At the funeral for Detective Wilden, Mona tries to sit with Spencer, Emily, Aria and Hanna, but they rebuff her and fail to make room for her to join them.
Mona disappears for the next few episodes. Nobody is sure where she has gone. In "Under the Gun", she returns and explains that she was tracking down the missing RV, which she discovered was stolen by Toby. Later on, Emily confronts Mona at the school's outdoor picnic tables and asks her for help in combating this new A, but she refuses, conceding that she is no longer the puppet master.
However, in "The Guilty Girl's Handbook", when Hanna comes to Mona for help to create a bold lie that she killed Wilden to protect her Mom, Mona surprises everybody yet again with an act of kindness, and confesses to killing Wilden.
In Into the Deep, Hanna finally gets a hold of Mona on the phone, who is seen packing her things in her room. Mona says the cops need someone to corroborate her story about Wilden before they can arrest her. Mona double checks that Ashley got out on bail and says, "You're welcome," before Hanna even has the chance to say 'thank you.' Mona is back in Radley.
In Now You See Me, Now You Don't, the girls receive a package. They open it and find a small white coffin, and inside is a doll that represents Mona. They get a text from A, which threatens that if they don’t find Mona, the cops will think that they killed her. Hanna calls Radley to see if Mona is still there.
In Who's In The Box?, in the halls, Mona approaches Hanna, but Hanna rebuffs her.
Mona start dating Mike in Bite Your Tongue.
In A is for Answers, it is revealed that Mona was the one who helped Alison run away.
In Surfing the Aftershocks, In the school hallway, Mona stops Aria and Hanna and asks her to sign a card for Mr. Fitz. Hanna takes the card from Mona to sign it, before passing it to Aria. Mona wonders what will happen when Ali returns to Rosewood high and reminds them that she knows Alison's story is bogus. Hanna asks her if she’s seen Noel and Mona replies by saying that he’s around somewhere, getting into mischief.
A flashback reveals that two months after Alison disappeared, Hanna was still Hefty Hanna. She is seen eating cupcakes by Mona who approaches her and comforts her about Ali’s disappearance. She says that being missing for two months is not a sign that Ali will return and that someone needs to take her place. Hanna is confused. Mona tells her that she can tell her the secret of being unforgetable.
Hanna sees Mona at school and flashes back to a time when Hanna was helped by Mona to be fabulous. Now she is thinner, Mona says that she needs a new wardrobe to go with her new style. Mona pulls out a dress of Alison’s that she left after a sleepover. Hanna says that it won’t fit, but Mona insists, making Hanna try on the dress. Hanna is happy to see that the dress fits.
While driving with Emily, Hanna flashes back to showing up in school with her new makeover, walking with Mona.
Back from Philadelphia, Hanna and Emily walk into the Brew, and Hanna spots Mona. Confronting her, Hanna tells Mona she essentially turned her into Alison. Mona says Hanna wanted the change as much as she did and that noone would remember the old Hanna.
Then, Hanna is at a hair salon, deciding that its time for a makeover and dyes her hair. Behind frosted glass, Mona is seen looking in when the silhouette of a woman comes to stand next to her
In Thrown From The Ride, at the school courtyard, Hanna and Aria are browsing through the books that are probably for giveaway. Hanna finds a copy of The Scarlet Letter, which belonged to Shana. Mona comes and picks up the book. She asks Aria and Hanna to get it for Ali, so that she can catch up before coming to Rosewood High. Hanna says that Ali will get her own copy. Mona says that Shana won’t be needing it anymore since she probably moved back to Georgia. Mona also wonders if Shana moving out may have a connection with Ali moving in.
In Miss Me x 100, when Mona ambushes Alison, Alison reminds Mona that she almost killed Hanna. Mona tells her no one feel worse about that than herself.
In A Dark Ali, Hanna, who is sick of Alison plans to go to her school's upcoming choir audition in an attempt to do something normal for once. At school, Hanna signs up for the choir auditions, when she hears Mona going through her runs. Irritated by Mona, Hanna shouts "Okay Mona, we get it. You can frickin' sing!" As the girls auditioning for the choir are called into the music room, Mona faints. Mona regains consciousness. She asks Hanna to get her bag, and when Hanna goes over to take it, she looks inside and finds Cyrus Petrillo’s mugshot.
Later, Mona is sitting in a car outside the police department listening to Tanner's bluetooth device, trying to track Cyrus down. Hanna gets in and comments that she recovered quickly. She asks whose car they’re in and says that she saw the mugshot of Cyrus in Mona’s bag. Mona says that she didn’t set Cyrus up, but she’s trying to find out who did. Mona tells Hanna to get out, and Hanna says that they both know Alison brings out the ‘A’ in her, so whether Mona set it all up or not, she doesn’t trust her. They notice Tanner, Kenneth and Alison get into a car outside the department and drive off. Hanna asks Mona how long until they release Cyrus, and Mona says it will be any minute, but Cyrus could go either out the front or the back. Hanna asks Mona why she said she fainted because of a panic attack, and Mona says that’s because she did; Alison scares her to death, which is apparently why she went on the offensive. She and Mona hear Tanner telling the police that Alison has identified the abandoned basement and for them not to release Cyrus Petrillo.
In Taking This One to the Grave, at Mona's house, Hanna and the liars show up, asking her help in bringing down Alison. Mona tells the liars that Alison stole her life from her when she crowned her Rosewood's biggest loser. Mona tells the liars that Alison was so convincing that even Mona was starting to believe her. Hanna asks whether this means that Mona will help the liars. Mona explains that even though she owes the four liars for everything that she has done to them in the past, she is worried to what Alison will do to her if she finds out that she has teamed up with the liars. The liars acknowledge her apology and begin to leave, but Hanna stays behind to get cookies from Leona. After standing with Hanna while she waited for Leona to bring her back a Tupperware container of cookies, Mona says that she’ll see Hanna at school, before walking away and back up the stairs. Pausing halfway up the stairs, Mona listens on as Leona asks Hanna if it’s starting again with Alison now that she’s back. Hanna tells her that she does not know what Alison is doing, as they are not friends anymore; however, she does believe that Mona is afraid of her, and adds that they all are.
The next day, in the bathroom at school, Hanna, Emily, Aria and Spencer have gathered to meet Mona. Mona tells them that Alison volunteered to take the polygraph test. Mona thinks Alison took the test because she is not having fun anymore — she can't play with her dolls (the liars) anymore as they are not letting her. She also believes Alison is A. After Mona hacks into and acquires the files related to Alison's polygraph test from the precinct, the liars and Mona watch the recording of Alison's test in Spencer's kitchen. The liars, Mona and Caleb then infiltrate Radley in an attempt to get Bethany's files.
On Thanksgiving day, at the Vanderwaal house, Mona is going through all the material they took from Radley while replaying Bethany's August 8th recording. Leona shouts for Mona to come down. As Mona leaves her room, Hanna texts her that Spencer has been arrested. She goes back into her house and locks the door while a figure in black with blond hair watches. Mona calls Aria and tells her that Alison lured Bethany to Rosewood, as she knew about the affair. Alison set her up because she was jealous and wanted Bethany dead. As Mona is in her room talking on the phone, the figure in black picks the lock on the front door and enters the house, creeping up to her room. Mona tells Aria that Alison is A and she can prove it. In Mona's bedroom, Mona looks into the mirror and says "Game over, Alison. I win." The figure enters the bedroom and Mona, thinking it's her mom, turns around and gasps, falling back onto her dresser. Hanna, Emily, Aria and Ezra enter the house to see blood everywhere and the place trashed. Hanna shouts for Mona. Hanna and Emily run upstairs to see if Mona is there. The scene cuts to outside the house as a long scream is heard.
The police eventually arrive and have taped the house off. Holbrook announces to the reporters that the investigation is ongoing and the incident has been ruled as a homicide. Although the police did not find a body, the amount of blood indicated the victim's wounds were fatal. Holbrook then declares that Mona Vanderwaal was murdered. Huddles among the people are the liars who are very upset. Hanna is sobbing when Officer Barry Maple approaches the girls and asks for their statements, but Hanna cannot bring herself to. The girls receive a text from A reading: "Its all your fault - A".
In How the 'A' Stole Christmas, while the Liars are walking through town, they stop in front of a shop. Hanna flashes back to the last time she was here. It was with Mona.This upsets Hanna. When Emily suggests that they should all make a wish, a sad Hanna replies "Wishes don't come true If they did, people wouldn't die". A lawyer approaches them and informs them that he is handling Mona’s affairs and she instructed him to deliver the letter to Hanna a month after her death. Hanna opens it and it is a bunch of drawings of Alison’s house and all of her hiding spots. The girls are certain that they can use Mona’s drawings to find proof that Alison killed Bethany Young and Spencer didn’t.
After the events of the DiLaurentis's Ice Ball, Hanna is sitting by the fire and looking at a photo of Mona. When Caleb asks her what is wrong, she says that Mona should be alive and that she didn't deserve to die. Hanna fells guilty and wishes Mona was there with them.
Mona's ghost makes an appearance in Alison's dreams.
- Alison showed both of them how to become pretty;she showed Hanna to throw up her food to lose weight, and she gave Mona fashion tips and how to become popular.
- Mona ran Hanna over with a car while they were still best friends.
- Hanna teared up Caleb's letter after her and Hanna first broke up.
- Hanna was the only liar that still had faith in her relationship with Mona even after she revealed herself as A.