Cath (short for Cather) is a freshman at college, and none to happy about it. Finding herself alone in the world for the first time, without her twin sister Wren by her side twenty-four hours a day, Cath lacks confidence and is terrified of new places, people and situations. Arriving at Pound Hall, her new home for the semester, she finds that she will be sharing room 2B with an abrupt, dismissive room-mate called Reagan, although Cath actually meets her room-mate's boyfriend, Levi, before she meets Reagan herself. Reagan isn't a freshman and not pleased to be sharing a room with one. She seems completely disinterested in being friends, and Cath is convinced that Reagan actually doesn't like her.
By contrast, Wren, always the more outgoing twin, and the one who insisted that they do not share a room during their college experience, has already made fast friends with her new room-mate, Courtney, and the pair invite Cath to join them at the Freshman barbecue. Cath declines, preferring to eat with their father before his drive home to Omaha. Cath is worried about her dad and fears he will not look after himself properly without his girls there to keep an eye on him.
Fearing even the simplest of new things, Cath eats protein bars alone in her room rather than find out where the dining hall is. The one bright spot in her college timetable is her Fiction Writing class. Normally reserved for upperclassmen, Cath has been awarded a place on it and is determined to shine. She is already a very successful writer of "fan fiction", creating new stories and endings for the characters in the famous Simon Snow fantasy series. She even has followers and fans of her own. Unfortunately, Professor Piper loathes fan fiction. As Cath is writing some fan fiction outside, under a tree (she is working on a final book for the Simon Snow series before the actual author releases the last one) she is approached by a fellow student in the class. His name is Nick, and she finds him interesting, and not unattractive. He asks about the writing exercise they had to do that week, writing about life from the perspective of an inanimate object. Cath wrote from the perspective of a lock, Nick, a pen, but he is already regretting that choice as it is rather pedestrian and not nearly as interesting as Cath's. Unsurprisingly Cath gets an A for the paper. Nick is intrigued with her as she is the lone freshman in the class, from which he deduces that she must be very talented, and probably a good person to know if he wants to raise his own grades in the class.
Due to Levi discovering Cath's hoard of protein bars, Reagan is convinced she has an eating disorder and tackles her about it. Shamefaced, Cath tells her that she does not have an eating disorder, but does, however, have a fear of new situations, and does not know where the dining hall is, which is why she eats protein bars in her room. This is her first real conversation with Reagan, and she admits that she believes Reagan doesn't like her. Reagan is surprised; she explains that her scholarship dictates where she rooms, and although she hates the situation, it's nothing persona. against Cath. She insists upon taking Cath to the dining hall and the two eat together from that visit on, usually punctuating their meals with observations about their fellow students whom they find endlessly entertaining.
Cath becomes overwhelmed with writing projects; as well as keeping her grades up in all of her subjects, her latest piece of fan fiction, "Carry On", is taking on a life of its own, with thirty-five thousand internet hits a day, fan letters to answer, and of course her fiction writing homework as well. Nick asks Cath to be his writing partner for their next assignment, writing by trading paragraphs to create the story, and making themselves more aware of plot and voice. They meet in the library and work longhand so that they can see the changing of authorship with each paragraph. Nick begins by creating a "love story" and Cath's paragraph makes the narrator of the story gay, naming him "Nick", and enjoying the easy way with which they can write together. Their story gets an A, and when they read it aloud in class they read each other's paragraphs, making it even more entertaining for the class. Nick makes Cath pinkie swear that they will always be writing partners when they are assigned a partner writing exercise in class, and she readily agrees. He also suggests that they do it again without an assignment as it will be good for their writing. Although she is absolutely swamped with writing already, Cath says yes.
Cath telephones Wren to talk about Nick, and her class, and Wren is drunk, and possibly high. She insults Cath's "Simon Snow" story, which she has never done before. Cath does not understand why Wren is changing so much and misses the way that she was before college. Cath spends her entire Saturday in her room writing, until Reagan returns from watching the football game that evening. She demands that Cath leaves the confines of their room and takes her bowling with Levi. Clearly the two of them have bowled before as both are very good. They invite Cath to go with them to Muggsy's Bar after bowling, and she almost says yes, but decides at the last minute to go straight home.
Abel, Cath's "home" boyfriend, calls her, which is unusual as they generally communicate by text message or email. He has met someone at the University of Missouri, and is breaking up with Cath. She is angry, and angered more when Abel tells her his new girlfriend has a higher SAT score than Cath achieved. Wren comes over that evening to comfort her, but has always thought that the two are not really boyfriend a girlfriend in the traditional sense, because theirs is mostly a non-romantic internet-based relationship. Cath cannot understand how she had believed herself to be in love all this time when she wasn't. Wren can't understand how Cath can write so beautiful and eloquently about how true love feels without being able to recognize the feeling in herself when it is there - or in the case of her and Abel, not there.
Levi and Reagan return before Wren has left and Levi is very attracted to Wren, unlike Reagan who finds identical twins rather creepy. Cath did not want Levi to meet Wren as everyone considers her to be the "hot one" and Cath feels like she pales in comparison.
That week,, Nick and Cath meet to discuss their new class assignment, a piece that has to have an unreliable narrator. Cath decides to use one of her fan fiction pieces. She wants Wren to come back home to Omaha that weekend to visit with their father but Wren is determined to stay and attend the football game, as well as drinking and going to a number of parties. Before she heads to Omaha with a student ride-share driver named Erin, Cath decides to go to the local Starbucks where Levi works to see if she can casually run into him. He spots her, and makes her his special gingerbread latte confection. Back in Omaha, Cath finds her father working feverishly on a marketing pitch for a fast food called Gravioli. They eat from their favorite Taco Truck, then Cath goes to bed whilst her father stays up working on his project. The following day Cath finds his ideas taped all over the living room. Taking an "if you can't beat them, join them" attitude, Cath decides to devote the weekend to her writing projects too, and they spend both Saturday and Sunday working together. Her father tells Cath that he has been talking to their mother, which infuriates her. Cath's mother walked out on them on September 11th, and Cath feels that this was even more of a reflection on her total self-absorption, to make a day of national mourning all about herself. Cath has no interest at all in speaking or reconnecting with her mother, Laura, and makes this very clear to her father, who is not particularly keen on the idea either, but had thought it might help heal his daughters who still carry so much of the experience of being left with them.
On Monday, back in class, they are given their final writing assignments - a ten thousand word essay. Although Nick teases Cath that she can churn out ten thousand words at lightning speed, she is not so sure. She receives an F grade on her unreliable narrator essay. Her fan fiction is deemed plagiarism, which Cath cannot understand as she only uses character created by someone else - the situations and plot twists are all her own work. She decides to hold an Emergency Dance Party for One, which involves cranking up a Kanye West cd very loudly and dancing herself better. Levi comes over to visit Reagan whilst Cath is still dancing, and decides to join in. As they are still dancing, Cath receives a text message from Wren who is at Muggsy's Bar, saying that there is an emergency and she should come right away. Levi offers to drive her and get her into the bar, but Wren is irate that they have come, saying that she texted the wrong "C" and that the text was actually meant for Courtney, the emergency call being that a young man she likes has just walked in and she should get there immediately. A bar customer nearby begins to make sleazy remarks about twins, and his fantasies about them, which Levi takes issue with and manages to convince Wren's boyfriend, Jandro, to take exception too, successfully enough to make Jandro hit the obnoxious bar goer. Wren is clearly drunk but refuses to leave with them. Before going back to college they drive to a twenty four hour truck stop for corned beef hash, which they share, and coffee, which is nowhere near as comforting as the gingerbread latte Levi made for her the week before. Cath begins to tell Levi about her fan fiction, never having explained it to anyone new before. He is intrigued and persuades her to read some to him. He is fascinated and seems to really enjoy spending time together. He invites Cath to a party at his house but she is reluctant to attend.
The day before Thanksgiving, Cath and Wren's father picks them up to drive them home for the hoiday. He won the Gravioli account but is hating every second of it as his original ideas are being tweaked and pulled so that they are not recognizable. Cath finds out that Wren is going to spend part of the Thanksgiving celebrations with their mother. This eventually turns into the entire Thanksgiving day celebration as she is tired and ends up spending the night with their mother and her new family, upsetting Cath even more.
Back at school, Levi is extremely panicked as he cannot find Reagan, who was going to help with his assignment on the novel The Outsiders. Levi has problems focussing on the written word and records all of his lectures to listen to later. The audiobook for The Outsiders was not available, and wanting to help, Cath begins to read the book aloud to him. They get closer and closer on the bed until they are kissing each other, before settling down to finish the remainder of the book. Reagan arrives home to find them lying together on the bed, arms wrapped around each other, and she is none too pleased about it. However, the following day she tells a contrite Cath that she and Levi were actually just friends, that they had dated during high school, but that it hadn't worked out, largely because she kept cheating on him. She knew that he liked Cath but had never thought much of it because she had been unaware that Cath had reciprocated his feelings. Encouraging Cath, they go to Levi's house party, but find him in the kitchen kissing another girl. Cath is embarrassed and upset, Reagan angry, and they leave without letting Levi know that they were there.
Although her real life romantic woes are piling up, Cath enjoys writing a love story with Nick, fixing and correcting his dialogue so that it sounds more legitimately feminine, and removing some of his more cliched love story elements. She discovers that Nick is planning on giving in their joint love story as his end of year, ten thousand word, essay, claiming that he was always more pivotal in its creation, and that she was more of a sounding board than a co-writer. Cath, by contrast, has a total writer's block over their final project and has yet to begin it.
Her father's co-worker, Kelly, telephones her from hospital to tell her that her father is in a psychiatric ward there, regaining his emotional balance. Wren thinks they should stay at school to finish their finals before going home to see him, but Cath goes right away. She ends up calling Levi, who drops everything to drive her to the hospital, promising to come and pick her up again when she has seen her father. Cath tidies up the family home, realizing that he hasn't been eating, or taking very good care of himself, and also realizing that he does not do either of these things without her at home making sure his is alright.
At Christmas, Wren wants Cath to accompany her to their mother's house, provoking a large fight, which does not improve when Cath finds matching birthstone necklaces for both twins around the tree from their mother. Cath tells her father she wants to move back home, skirting around the issue of why so that he does not realize the real reason for this is to take care of him. He doesn't want her to quit mid-year, and she is persuaded to return, finding that she received an "incomplete" for her writing class. Professor Piper gives her the opportunity to write her paper and get a good grade if she completes by the end of the semester. She then asks if she assisted Nick with his assignment, telling Cath that she could recognize some of her style in his work.
Levi comes to apologize to Cath for the kiss that she witnessed at his party. He tells her that when he kissed Cath, it meant something special and that he really likes her a great deal. They talk, and arrange a date. Reagan sets them some groundrules for what they can and can't talk over with her, and soon Levi and Cath are naturally spending all of their free time together. He wants to drive her home and meet her father; she is unsure, but convinced, but the weather is treacherous and it soon becomes clear that the trip was a terrible idea. Because of the heavy snow, Cath and her father insist that Levi stays the night at the house. Cath's father likes her new boyfriend and is happy to see that she is at last finding her place in the world whilst at school.
Cath's mother calls her from the hospital where Wren has been admitted with alcohol poisoning. The hospital staff had scrolled through Wren's cellphone and found her number, telling Laura that they always call the mother in this situation. Cath can barely stand to be near her and desperately wants her to leave. Laura tells her that she would like to develop a relationship with Cath as well as with Wren but that it is the wrong time to do so. Cath tells her that this is the only chance she will get, but true to form Laura leaves without taking it. Wren wakes to find Cath at her bedside. When she is allowed to leave, she finds Jandro sitting in the waiting area, along with Levi, who had received all of Cath's voicemails and texts, but whose replies had never been received as Cath's cellphone battery had died. Wren is not nearly as contrite as her father would like, and he seems to visibly shake off his emotional problems when he realizes that he needs to be the adult, the strong one, for the good of his children. Unimpressed with Wren's defense, "everybody drinks", he initially tells her that she is moving home, no argument, no school. He is subsequently persuaded to let her return to school, as long as she returns home under his supervision every weekend. Wren is resentful and petulant but has no option other than to agree. She is shocked to hear that Cath has a boyfriend and even more shocked to have her sister held up as the example of well-spent college years.
The first night back at school after Wren's hospital stay, Cath goes to Levi's house. They read more fan fiction and he admits that he is falling in love with her. She is happy, and happier still because she and Wren are back on speaking terms. She feels strangely and inexplicably more complete. They discuss their mother again and Cath makes it clear once and for all that there will be no reunion between Laura and herself.
Still having problems with her final essay, she does, however, manage to finish her fan fiction finale before the last Simon Snow book is released. Nick comes to her room with something on his mind and wants a private conversation, but fortunately Cath is backed up by Levi, Reagan and Wren who refuse to leave them alone, so he explains to all of them that his love story essay has been selected for the Praire Schooner, the school's literary journal. This is a great honor. Professor Piper has insisted that he must share credit with Cath in order for it to be published. Cath says that she doesn't want the credit, but it is not a negotiable thing, and if she doesn't agree to have her name on the essay too, it cannot be published. She tells him that she still won't accede but that he is a good writer and he will have more opportunities. She is finally able to feel some closure on his betrayal of their writing partnership.
Cath finally admits to Levi that she loves him, and although their situation will clearly change over the summer, they vow to make it through and survive as a couple; Levi has been in love with her for quite some time. Now that her Simon Snow fiction writing is over, Cath is able to move forward with real-life romance and relationships, leaving the fictional world behind.