|“|| Hanna: What's worth losing everything?|
— Lucas and Hanna
"There's No Place Like Homecoming:" When Hanna joins Sean's abstinence club at school, "Love Waits," she finds a surprising ally in the equally reluctant Lucas. The members are asked to role play situations in which they would be pressured to have sexual intercourse. Hanna is called to take a turn - with Lucas. Unenthusiastic, she pretends to ask Lucas to make out, and after initially refusing to play along, he then says "yes," making Hanna finally smile and Sean see red.
As yearbook editor in charge of photos, Lucas attends homecoming solely in order to photograph the event. At the dance, Mona and Hanna get into a heated argument when Mona makes nasty comments to Lucas, who has come to the dance as photographer 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.
Later, he gives Hanna a ride to the therapist's office so that she can steal Jenna's file. She keeps Lucas in the dark as to what she is doing, but he is happy to be hanging out with her. He confesses that besides for taking pictures, he had gone to Homecoming in order to elect Hanna Homecoming Queen.
The next day (in The Homecoming Hangover), he takes multiple shots of the homecoming king and queen, eventually frustrating the homecoming king with his suggestions, such as having Hanna sit on his lap. When Sean gets angry at Hanna, Lucas snaps a photo of Sean, roiling him further. Later, Lucas and Hanna have fun looking at online videos together, whereas Sean thinks the videos are stupid, proving how much more Lucas and Hanna have in common than her current boyfriend, Sean.When Hanna decides to help out with the Marins' financial situation, she agrees to put up a lot of her old clothes and handbags up for auction online with the help of her new ally, Lucas, who gives her the idea in the first place.
Hanna and Lucas grow closer, as Lucas continues to score Hanna big bucks selling her lesser used accessories on the internet. But, Mona is not enthusiastic about this new relationship development and mercilessly taunts Lucas for not being manly enough. 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! Later, Lucas thanks her for Mona’s improved treatment of him.
At the hospital after Hanna's accident, an attentive Lucas gives Hanna a sweet kiss as she sleeps. He brings her three choices of puddings when she awakens, trying to advance their relationship, but feels brutally rebuffed when she and tells him – in truth, that she sees him much more as a friend. He wishes that she would lie, rather than be so brutally disappointing, but she refuses.
At Hanna’s homecoming party, Lucas drinks too much. Still upset from Hanna refusing to be more than friends, he makes a big scene. Later, he confesses to trashing Alison's memorial, though Hanna forgives him and promises to keep his secret under tabs. He was upset by the memories of Alison's terrible treatment of them all this time and finds it hard to understand why Hanna could ever be friends with such a mean person.
At the Dance-A-Thon, "A" instructs Hanna to repeatedly dance with Lucas and then break his heart, in exchange for her mother's money back. Sean is unforgiving of Hanna's unceremonious treatment of him after several dances with Lucas, leaving her to slow dance with him. At the end of the night, Lucas also feels rejected when Hanna turns down his offer to give her a ride home. Emily, though very drunk, catches onto Hanna's poor treatment of Lucas and comments that Alison would be proud. Hanna feels very remorseful.
In "For Whom the Bell Tolls," Lucas is suspicious of Mona and what she had to do with Caleb leaving town. Mona tries to intimidate Lucas to forget about it, tempting him with the prospect of obtaining Hanna, but Lucas clearly doesn't take the bait, as later we see Lucas and Caleb in a car together! Lucas is driving Caleb back to Rosewood, Pennsylvania (from Arizona?).
When Lucas and Caleb arrive in Rosewood, Lucas protectively warns Caleb not to hurt Hanna again.
When Hanna is no longer allowed to see her friends, she decides to help Lucas with the yearbook. At first, Lucas wonders why Hanna is being so nice to him, worried that she has ulterior motives—but Hanna insists that people can change. She even gets a pretty girl named Danielle that Lucas is so obviously crushing on to agree to a date with Lucas.
In "Blind Dates," Lucas is nervous about his upcoming date with Danielle, so he asks Hanna to double with him and tells her to bring Caleb. Unfortunately it backfires, as Danielle thinks that Hanna is interested in Lucas. To convince Danielle that there is no longer anything between her and Lucas, Hanna recruits Caleb to better pretend to be on a real date and in a romantic relationship with each other. It works, and Danielle reaches for Lucas' hand. Lucas now understands Hanna's motives to be pure. He thanks Hanna later for helping him with Danielle and acting so un-Alison like. Lucas' words play a major role in helping Hanna get over Alison and the effect her bullying had on her self-esteem.
Hanna and Lucas' friendship seems to have grown strong during the month between "Over My Dead Body" and "Through Many Dangers, Toils, and Snares." He has been helping her take down all the unflattering community service photos of her that have surfaced on the internet. He tells her she looks pretty despite her protests. There is tension between Lucas and Caleb over Caleb's plans for the future and potential for hurting Hanna.
In "A Hot Piece of A," Lucas reluctantly helps Hanna study for a test and plan Caleb's surprise party. It seems he is hiding a big secret from Hanna, even calling a crisis hotline to get it off his chest. Emily and Spencer try to convince Hanna that Lucas is A's helper, the one that tried to kill Emily in the greenhouse, but Hanna refuses to entertain the idea without proof. Lucas and Hanna take the rowboat from Spencer's lake house to the other side of the lake to set up fireworks. Lucas stops rowing half-way across so they can talk. Hanna gets spooked and pushes Lucas out of the boat.
In "Let the Water Hold Me Down." after the incident, Hanna tells the others she is sure Lucas is still alive. The next day she finds out from Lucas' parents that he called them and is staying with a cousin for the time being. Caleb, however, doesn't buy it and wants to search for Lucas. Hanna isn't quite as eager because she is afraid Lucas could have been helping "A," but can't tell Caleb that. That night, Hanna notices the wind blew the door open, and thinks the latch is broken, but really Lucas broke in to the house.
Lucas slips into Hanna's bedroom while she is in the hall talking to her mom. He surprises her there, claiming that he never wanted to hurt her. Hanna asks what he did to Caleb while covertly calling Caleb on her cell. Caleb, who is already downstairs, gets the call and rushes up to Hanna's room, hearing Lucas' threatening voice in the background. Caleb asks what Lucas did and where he has been. Lucas reveals why he was on the hotline: He lost $4,000 in a bet over a basketball game, money which belonged to Caleb. It was a sure thing until the team got disqualified. After the rowboat incident, he drove all over selling his comic books to try to get some of Caleb's money back. Now they're all on good terms again, but Hanna now is unsure of who they met in the greenhouse.
In "She's Better Now" Hanna is worried about Lucas when Mona whispers something to him but he doesn't say anything to her. The next day Lucas knocks on Hanna's door with the last of the money he owed Caleb. Hanna asks him about his leg and he says that he got in a skateboarding accident. Hanna asks Lucas what's going on between him and Mona but he says nothing, apart from telling her that Mona had been sneaking out of Radley Sanitarium for a long time, and he won't say why.
The Gloves Are On Hanna runs into Lucas at the brew, apparently Lucas is doing very well for himself. With several different homes one of which in Rosewood. He was unaware of Hanna and Caleb’s break up.
Hanna goes to Lucas for his help. She asks if he was in town the night Charlotte died. He asks why, she tells him what she and her friends were doing and tells him the police think she may have been involved so she asks Lucas if he could say they were together. Hanna immediately regrets asking, but Lucas says if Hanna needs him then he’s there for her.
When Hanna is being questioned by Lorenzo, who finds it difficult to believe that she reached out to someone she hadn't talked to in five years, Hanna says that she and Lucas were close and that none of the other girls were awake for their late night snack. Lorenzo invites Lucas into the room and says that Hanna doesn't remember inviting him into the room. Lucas says that she didn't and that there was a man leaving as he got there, but didn't get a good look at him. Lorenzo asks why Lucas was so eager to drop off food in the middle of the night and Lucas merely replies that Hanna called and he was happy to hear her voice. Hanna said that they talked until the sun came up and, when Lorenzo asks if Lucas had been drinking, Lucas says he hadn't had anything other than ice water. Lorenzo asks if he left the room, causing Lucas to say that he went down the hall to the ice machine. However, Lorenzo says that Radley doesn't have an ice closet on the third floor.
Hanna shows up at Lucas's flat saying she had no right to ask that of him. He says she doesn't have to answer him, but asks if she had anything to do with Charlotte falling off the bell tower. She says that she didn't, but that he is braver than her mom; she wanted to ask Hanna the same question, but was afraid of what the answer might be. After Hanna says that waking up in her old room gets harder every day, Lucas gives her the keys to his flat since he'll be leaving for San Jose and tells her that she can stay as long as she wants. Later, Lucas makes dinner for Hanna.
Did You Miss Me? While Hanna is on the phone with Jordan, Lucas runs diagnostics on a tablet. She says that it's a good idea to stay in Rosewood because, if she was in New York, she'd just be thinking about Aria and the others. She adds that they're her friends and says that she'll call him later. Lucas looks up and asks if he'll get an invitation to her wedding, then adds that he was half-expecting to meet Jordan when he came back. Hanna says that Jordan is a little phobic of small towns, causing Lucas to say that he used to think that but big cities changed his mind. Hanna then gives Lucas a gift, in the form of a few ties, thanking him for letting her stay there: she also wrote post-it notes saying which tie goes with what. Lucas talks about how he came back because he wanted to look for property, then adds that maybe he's giving Rosewood a second chance. Hanna agrees saying that they left so fast that they didn't realize what they left behind, and they smile at each other.
While Hanna and Caleb are talking in Lucas' loft, Lucas accidentally scares them by lighting the fireplace. He tells them from upstairs that he wanted to make sure it worked from anywhere in the apartment. After Caleb leaves, Hanna sees a picture of an empty factory and Lucas tells her that he's buying it; she asks what it will look like when it's finished and what he'll do with it. He shows her a picture of what the finished product will look like and says that he can do whatever he wants with it, before asking what she would do with it. She says indoor miniature golf, but he wants a serious answer. He says "If somebody told you that you could try anything, you know, start your own business. What would you do?". She tells him not to joke like that and he asks, "Who's kidding?" and smiles. Hanna says that she would set herself up with new designers and start her own brand. Lucas says that it's a deal. A stunned Hanna is speechless and Lucas says that this will be a good way for her to keep one foot in Rosewood and figure out what she left behind. Hanna is hesitant to accept the offer, but Lucas assures her that the offer still stands and that she should talk to Jordan about it.
Lucas [about Hanna]: Girls like her don't approach guys like me unless they have deep-seated self-esteem issues and a drinking problem... I have the upper body strength of Screech, and I spend my weekends playing Wii, alone. I think my virginity is pretty well safeguarded.
Lucas [telling Hanna she looks pretty in photos]: You do, sort of, in a post-apocalyptic, ragtag-band-of-survivors kind of way.
[Lucas' hand touches Hanna]
Hanna: For what?
Lucas: I didn't mean to invade your personal... Skin.
Hanna: It's okay. The Leprosy cleared up.
Lucas: Pudding palooza! Vanilla, tapioca, butterscotch.
Hanna: Uh, tapioca. I like the little bumps.
Lucas [referencing her cast]: That's starting to look like the Declaration of Independence.
Hanna: You know, Lucas, you don't have to keep skipping school I'm okay.
Lucas: I told them I was doing community service.
Hanna: And they believed you?
Lucas: I have a very believable face. I plan to use it in politics.
Hanna: Well, you're a good friend.
[Lucas and Hanna are in the hospital talking about the night before]
Lucas: Did Lucas actually kiss me when he thought I was asleep?
Hanna: Yeah. Things like that.
Lucas: I thought you might had been awake. And then I thought, if she was awake, and she didn't scream then that was a good sign.
Hanna: Well, I was too surprised to do anything.
Lucas: Really? You were that surprised? Me wanting to kiss you was so outside the realm of probability?
Hanna: No! No, it's not that it's just... You know, I thought that we were friends. Look, I like you Lucas.
Lucas: I feel like you're breaking up with me but we were never really together.
Hanna: Lucas, I am being honest with you. And, besides, I have a boyfriend!
Lucas: And I think you deserve a better boyfriend.
Hanna: Well, that's between me and Sean. Look, I like you way to much to lie to you. And, that's something I used to do all the time.
Lucas: Well, can't you just keep lying for old-times sake?
Hanna [shaking head]: I'm sorry.
[Lucas starts to walk out]
Hanna: No, wait, Lucas you don't have to leave.
Lucas: No, but if I stay then you're going to think that I'm okay with this and I'm not. I'm sorry. But I'm just being honest.
Lucas [to Hanna after she pities him]: Don't. Please. Don't make me like you. It's too hard.
Lucas [offering to take Hanna home]: Look... I know Sean took off and... I was thinking that since you guys were now over...
Hanna: Lucas, that's really sweet of you to offer but... Emily's kind of... She needs me right now and I already told Spencer I'd go with her so...
Hanna: I miss you.
Lucas: I miss you, too.
Caleb [when Lucas brings him back to Rosewood]: Why are you doing this?
Lucas: Because Hanna deserves to be happy.
Lucas [when Hanna asks him to be her alibi]: Hey. You need me. I'm here for you.
Lucas: So, do I get an invitation to the wedding?
Hanna: Of course, you do.
Hanna: Oh! Um, I picked up a few ties that I think could go with the shirts I saw in your closet.
Lucas: You did not have to do that.
Hanna: Well, it's just a little thank you for letting me stay here. Oh, and I put post-its on what goes with what.
Lucas: Perfect! Granimals for grown-ups.
Hanna: Hey, what-what is this?
Lucas: Oh, it's the empty factory I'm buying near the lake. And this, is what it's going to look like when it's finished.
Hanna: Wow, that's really nice. What are you gonna do with it?
Lucas: Anything I want to. What would you do with it?
Hanna: Um... Indoor miniature golf?
Lucas: No, seriously, what would you do? If somebody said that you could try anything so create your own business. What would you do?
Hanna: Don't kid like that, Lucas.
Lucas: Who's kidding?
Hanna: Well, I would... Set myself up with some new designers, start my own brand, you know get out of the city away from all the distractions.
Lucas: Deal. Research and development. It can mean whatever we say that it means. Looks, this will be a good way for you too keep one foot in Rosewood. Figure out what you left behind.
Hanna: I think you think I'm somebody I'm not. Everyone thinks I'm somebody I'm not. Somebody smarter, braver, sharper. But I'm not.
Lucas: Yes, you are. That's the point.
Hanna: Lucas? I believe you. That you weren't part of what happened to us. But why is the factory for sale? I mean, was our business partnership ever real?
Lucas: I think you're so talented, Hanna. I just... I had trouble getting other people to take a chance on you.
Hanna: Well, what about the investors?
Lucas: You're looking at him. I was too embarrassed to tell you that I couldn't do it anymore.
Hanna: So, my friends made your life miserable in High School, they almost broke your collar bone tonight, and now you're telling me that I lost all your money?
Lucas: I'll make it back again. Besides, it was worth it.
Hanna: How was it worth it? What's worth losing everything?
Hanna: Thank you. I never doubted that you were--
Lucas: I know. I know.
- Hanna originally only knew Lucas through his interactions with Alison, when Alison would torment him and bully him. During these moments, Hanna just stood by and watched, something that Lucas resented.
- It wasn't until years later, that he told Hanna that he would write angry emails to Charles about her.
- Lucas had a crush on Hanna throughout High School, but never had the courage to tell her.
- When the Liars' parents forced them to spend time apart, Lucas let Hanna help him and the yearbook committee after school so she wouldn't be alone.
- He helped her sell some of her extra fashion items online so that she could make some extra money.
- He came to visit her in the hospital after she was run over by A. The first time he visited he was sent away by Ashley as Hanna was still unconscious, the second he visited her in the middle of night and gave her a kiss on the forehead while she was sleeping, and the third was the next day when she was awake and alert.
- She asked him to be her alibi for the night of Charlotte's murder, which he originally agreed to. However, he was caught in the lie and told the truth but assured the police that Hanna wasn't involved.
- He let her stay in his loft while she was living in Rosewood. As a thank you, she bought him ties to go with the shirts in his closet, and put post-it notes on them so he knew what ties went with what.
- He offered to help her start her own business, and all-but gave her a million dollar line of credit.
- In the books, Lucas and Hanna were close friends.