Fiona met Charlie while Charlie was modeling for an art class that Fiona was taking with Holly J over spring break. Fiona instaltly became attracted to Charlie, and made plans to see her outside of class. While the two were hanging out, Fiona realized that they had little in common, so she began to pretend to have the same hobbies and interests as Charlie. Eventually Charlie moved in with Fiona, after her roommate kicked her out, but that was short lived after Fiona accused her of bringing bedbugs into her condo. The girls remained friends after they split up.
In Spring Fever, Fiona develops a crush on Charlie when they meet in Holly J. Sinclair's drawing class, for which Charlie is a model. Fiona then awkwardly talks about motor scooters with Charlie, trying to display common interest, and they make plans to ride together even though Fiona lied about having a scooter in the first place. The next day, Fiona admits she lied to her about being interested in scooters to impress Charlie. After Fiona confesses her sexuality to her, Charlie tells her she is a lesbian as well. When they run into each other later, Charlie gives Fiona a ride on her scooter, as Fiona had never ridden one before. Fiona is inspired by Charlie to buy a scooter and get her license, and reveals to Holly J. that she is coming over to sketch later at her place. When Charlie arrives, she models for Fiona, who in turn, puts on a bikini for Charlie to sketch her. Charlie calls her "one of the most beautiful things in the world", and they begin to make out, before Fiona pulls away, looking uncomfortable. The following day, Fiona and Charlie decide they were going too fast, and decide to stay friends first above anything.
In Paper Planes (2), Fiona and Charlie patch things up after the bedbug incident. Charlie suggests they celebrate their first night bedbeg free with champagne. Not having told Charlie she's a recovering alcoholic Fiona is slightly uneasy. Noticing Fiona's reaction, Charlies thinks she's never tried it, but Fiona says it's because she likes her so much and doesn't want to mess anything up. Charlie reveals that she's falling for Fiona also, and they share a kiss. This marks the beginning of their relationship. While in drama class, Eli takes notice in how Fiona is glowing and she says that she had an intimate moment with Charlie, and hasn't told her she's a recovering alcoholic. Eli advises that she tell her and that if she really likes her, she'll deal. Later at her condo, Fiona walks in on Charlie preparing dinner, and she pours the two a glass of champagne. Fiona reveals to Charlie that she was once an alcoholic and went to rehab for help, but she has control. Feeling anxious, Fiona runs to call her mom, and later tells Charlie her therapist says she's not ready to be around alcohol. Charlie seems willing to give it up, but is disappointed that Fiona waited until she moved in to tell her. Fiona says she doesn't have to do anything, but the fact she waited so long proved she isn't ready to be in a relationship. Charlie asks if she'll be moving out and moving back in with her mother. Fiona apologizes and says she really wanted them to work. She asks Charlie if she's okay and she responds by saying she's a big girl.
In Cry Me A River (1), Fiona is short an art credit and is placed in 11th grade Drama class. Fiona is left with no group and excuses herself from class. Fiona goes to see Holly J. getting ready to have her graduation photos taken and talks to her about her woes of not being able to make friends easily. Holly J. suggests spending time with Charlie so, Fiona goes to Charlie's job to have lunch with her where she sees that Charlie's friend was also there and invites her to eat with them. Later, Fiona takes Charlie back to her house when her mom comes home early and yells at Fiona for skipping school. Charlie leaves and Fiona tells her mom about how she feels lonely now that she has to be in 11th grade classes and promises to not skip class again. The next day, Fiona is about to leave for school and is trying to get a hold of Charlie on the phone to apologize for her mom telling Charlie to leave but she won't answer and Fiona is scared that Charlie's mad at her.
In Cry Me A River (2), Fiona tells Holly J. about what happened the day before when she skipped school to hang out with Charlie. She worries about the fact that Charlie isn't calling her back and leaves to go talk to her in person. She shows up and watches Charlie argue with her friend. The fight ends when the girl hugs Charlie close, leaving Fiona disappointed. Fiona goes to talk to Charlie. Attempting to make her feel better, she irritates Charlie, who tells Fiona to go back to school. Fiona tells Holly J. what happened. In drama, Eli begs Fiona to convince everyone not to make a play based on a TV show. Fiona is made director and Eli the writer. After talking to Eli, Charlie shows up and apologizes to Fiona for snapping. Charlie reveals that her ex kicked her out of their apartment, which is why she was in a bad mood, but she doesn't want to talk about it. Fiona tells her that she was made director and they go to hang out. Fiona has Charlie move in with her.
In Paper Planes (1), Fiona wakes up to find that Charlie is already up, dressed, and has gone for a coffee run. Fiona hands Charlie her Key. Charlie reveals that she has early morning classes, works in the afternoon and then volunteers at a homeless shelter. To Fiona's immediate dismay, Charlie also has a cat named Mr. Tuxedo Pants which she brings in. Then they play with him. Fiona comes to talk to Holly J. about Charlie. Holly J. is shocked to find out that Fiona never told her mother about Charlie moving in. Fiona blows it off, figuring that when Mrs. Coyne sees how happy Fiona is that she won't kick Charlie out. Eli talks to Fiona about the play, and she explains that she has an allergy to Charlie's cat. Eli thinks the bites are something more and jumps away from Fiona when it's revealed she has bedbugs. Fiona has an exterminator come over,who confirms that she has bedbugs. She realizes that Charlie brought them with her. When Charlie comes home, they argue over the fact that Fiona assumed Charlie brought them with her because of all the places she's been. Fiona and Charlie patch things up and talk about their lives. Fiona's mother reveals she brought the bedbugs.
In Take a Bow (1), Fiona is out with Anya and Holly J. and runs into Charlie, who invites her to her art show. Holly J. and Anya turn out to have dates for prom, leaving Fiona alone. Fiona meets Eli at his locker and asks him to prom, which he turns down as he is a server. Eli encourages her to ask Charlie to go with her. Fiona meets Charlie at her art studio and startles her. They discuss their breakup, and Fiona offers to take care of Mr. Tuxedo-Pants. In return, Charlie says she'll go to prom with Fiona. Holly J. meets Fiona at her house, as Fiona cleans (her mom is coming the next day) she tells her she is going to Prom with Charlie. Fiona reassures Holly J. that everything is okay. At Charlie's art show, Charlie shows Fiona the portrait she did of her. Fiona is amazed and while Charlie goes to seal a deal and Fiona decides to buy the painting. Charlie introduces Fiona to her girlfriend Meredith, to Fiona's shock and disappointment. Fiona takes a drink. Charlie calls Fiona. She lets the cat leave, and drinks some more.
In Take a Bow (2), Fiona runs into Charlie who confronts her about the bottle of alcohol. Charlie tells her to call someone and Fiona says there is no one she can talk to, revealing her deep loneliness. Fiona also tells Charlie that she lost the cat when she was drunk. Charlie gets upset and tells her she pushes people away. Fiona tells that Charlie that she will help find Mr. Tuxedo Pants. However, Charlie tells her that he was already found. As they are looking at Fiona's painting, Fiona tells her that she will go to rehab instead of prom.
- Charlie was Fiona's first girlfriend.
- Fiona lost her virginity to Charlie in Paper Planes (2).
- Start Up: Paper Planes (2) (1111)
- Broke Up: Paper Planes (2) (1111)
- Reason: Charlie bought champagne and Fiona had to call her therapist, which led her to realize she wasn't ready for a relationship.