One month after his breakup with Tessa Young, Hardin Scott meets an unknown man whom he rebuffs when he attempts to talk to him. Meanwhile Tessa, on her first day as an intern at Vance Publishing, shares an awkward encounter with her new coworker Trevor Matthews. Kimberly takes her to her office where she ends up working all night. The next morning, Christian Vance, impressed with Tessa’s work, takes her to a Seattle conference with Kimberly and Trevor. Hardin returns to the frat house after getting a tattoo, where he meets up with his friends but leaves after Molly tries to seduce him to forget about Tessa.
Tessa goes to a nightclub with Trevor and Kimberly to celebrate the expansion of Vance. In a drunken stupor, she calls Hardin, who arrives to see Trevor half dressed due to Tessa trying to clean Trevor’s suit which she accidentally spilled wine on. Trevor leaves and Tessa fights with Hardin before the two have sex. The morning after, Tessa and Hardin argue about the previous night, which leads to her telling him that it was a mistake and that she kissed someone at the club. Hardin retaliates by lying that he slept with Molly. Trevor gifts Tessa a new car with insurance and she kisses him. She returns to the apartment where she and Hardin previously lived to retrieve the rest of her belongings and sees a Kindle which was gifted to her by Hardin for her birthday. Hardin’s mother, Trish, arrives with him and the pair are forced to pretend they are still together as Hardin didn’t inform her about their breakup. The next day, Tessa leaves to meet her mother, Carol, and her ex-boyfriend, Noah. Tessa arrives in front of her mother’s house, only to learn from Noah that her father came to see her but Carol sent him away. Angered, Tessa reunites with Hardin.
Hardin and Tessa spend the day together but are interrupted by Kimberly asking if the pair could babysit Christian’s son, Smith. Afterwards, Hardin gifts her a charm bracelet and the pair confess their love before having sex in Tessa’s office. On Christmas Day, Hardin, Tessa and Trish go to Ken and Karen’s to celebrate. Jealous over Ken’s new family, Hardin gets drunk and punches Ken after an argument about his mother’s assault. Trish berates Hardin and leaves for the airport. When Tessa leaves, Hardin gets into a drunken rage before passing out. Tessa confesses the incident to Trevor, who warns her that her relationship with Hardin won’t end well.
On New Year’s Eve, Tessa joins Hardin at a party. Hardin speaks to Jamie, whom he had previously bet on, to ask for her forgiveness. Tessa and Molly get into a physical fight, which Hardin breaks up. He carries Tessa to his old room, where they have sex. Unbeknownst to Tessa, Hardin reads a text on her phone from Vance about Tessa moving to Seattle with the publishing company. Angry, Hardin leaves the room and runs into Jamie, asking her to keep their conversation between them. Tessa misinterprets this as Hardin cheating on her and impulsively kisses a stranger in front of him, despite his attempts to explain. The two fight and Hardin repeatedly ignores her; when he calls her the next day, she gets distracted, causing a car accident. After being chastised by Landon, Hardin calls Tessa, but Trevor answers the phone and tells him to stay away from her. Hardin writes a letter to Tessa explaining his past with Jamie and ends their relationship. Trish convinces him otherwise and he goes to Christian’s farewell party.
Christian provides a toast for his colleagues and proposes to Kimberly, which she accepts. Trevor reveals to Tessa that he told Hardin to stay away from her. Hardin appears at the party, upsetting Tessa. Hardin follows her outside and the two leave the party together. Hardin gets a new tattoo, promising to himself and Tessa that he’ll never leave her. As they are leaving, the unknown man whom Hardin met before reveals himself to be Tessa’s father. In a post credits scene, Trevor practices in the mirror to ask Tessa out for a date.