Autumn is the novel’s protagonist. At the beginning of the novel, Autumn is just beginning high school, and has a naive understanding of relationships and intimacy. As the novel progresses, Autumn fosters several relationships, including with Jamie, a boy whom she imagines she will marry someday, and with several friends who become her support network. At the same time Autumn struggles with the friendship she once considered her most important, her relationship with neighbor, Finny.

The novel highlights how friendship can transform into romantic love. Finny and Autumn have known each other since birth and were best friends until the end of middle school. In eighth grade, Finny kissed her and Autumn was not mature enough to understand the implications, causing them to pull apart. All through high school, Autumn continues to misunderstand what Finny’s intention was that night, and she struggles with a relationship that was once close and is now almost nonexistent.

The novel explores mental health through the characters of Autumn and her mother. Throughout the novel, Autumn makes small mentions of her mother’s depression, foreshadowing the onset of her own depression. When Autumn becomes depressed, her mother immediately takes her to the doctor and Autumn begins taking medication.