Plot
Mavis Gary (Charlize Theron) is a divorced, 37-year-old ghost writer of a series of young adult novels, who is on deadline with her editor to finish the last book of the soon-to-be-cancelled series. Mavis receives an e-mail with a picture of the newborn daughter of her high school boyfriend Buddy Slade (Patrick Wilson) and his wife Beth (Elizabeth Reaser). Believing this to be a sign she and Buddy are meant to be together, Mavis leaves Minneapolis and returns to her hometown of Mercury, Minnesota, to reclaim her life with Buddy, under the pretext of overseeing a real estate deal.
Upon arriving after multiple listens of "The Concept" by Teenage Fanclub on an old mixtape Buddy gave her in high school, Mavis arranges to meet him the next day at a local sports bar, for old times' sake. In the interim, she goes alone to a different bar, Woody's. There she reconnects with a former classmate she barely remembers, Matt Freehauf (Patton Oswalt), who became partially disabled after being beaten by jocks who erroneously assumed he was gay. Matt tells Mavis that her plan to destroy Buddy's marriage is irrational and selfish, but she ignores him.
The following day, Mavis meets Buddy at the sports bar, where they run into Matt, the bar's bookkeeper. On their way out, Buddy invites Mavis to a performance of Beth's "mom rock band". In the interim, Mavis spends another night getting drunk with Matt, who distills homemade bourbon in the garage of the house he shares with his sister Sandra. When Mavis attends the concert of Beth's band, the other moms are resentful of Mavis, who they remember as the "psychotic prom queen bitch". When Beth's band performs, the lead singer dedicates their opening song to Buddy from Beth; much to Mavis's dismay, it is "The Concept".
Beth wants to stay out longer, so Mavis offers to drive the drunk Buddy home. On the lawn they share a kiss that is quickly broken up when the babysitter opens the front door to greet them. The next day, after an awkward encounter with her parents, Mavis is invited to Buddy's daughter's naming ceremony. She later goes out drinking with Matt again, during which Matt tells Mavis to grow up. The following day, Mavis attends the party, where she declares her love for Buddy, but he rebuffs her. Everyone at the party is called out to the lawn to await a surprise Buddy has prepared for Beth. Mavis, who has been drinking at the party, collides with Beth, who accidentally spills punch on Mavis's dress. Mavis insults her, and in a profanity-laced tirade tearfully reveals she became pregnant with Buddy's baby years ago, but had a miscarriage after three months.
Buddy, who has been preparing a drum-set gift for Beth in the garage, opens the garage door and belatedly learns what has transpired. Mavis asks him why he invited her. He reveals it was Beth's idea, as she feels sorry for Mavis. Humiliated, Mavis leaves the party and visits Matt, where she breaks down in tears and, later, initiates sex. The following morning, while Matt sleeps, Mavis has coffee in the kitchen with Sandra, who still idolizes her. Mavis talks about needing to change herself, but Sandra says Mavis is better than the rest of Mercury and should not change. Mavis says she agrees, and prepares to return to Minneapolis. Sandra asks to go with her but Mavis declines and leaves alone.
In a diner on her way home, Mavis writes the last chapter of the book, in which the main character graduates high school, quickly leaves her past behind and looks forward to the future. Afterward, in the parking lot, Mavis contemplates her crumpled car.
