The novel’s protagonist is Calliope Snow, a middle school girl who goes by Calli June. She lives with her mom, and her father passed away in a car accident prior to the events of the novel. Her father died during a snowstorm, which is why Calli chooses to not go by her given last name. Calli has Tourette syndrome, as well as obsessive-compulsive disorder and anxiety. She was told by her mother and doctor at a young age to hide her symptoms, especially her tics. Terry constructs Calli as a semiautobiographical figure to portray the harms of such misunderstandings of Tourette’s and explore Neurodiversity and Self-Acceptance. In the novel’s subplot, Calli’s mother has moved their family 10 different times after difficult break-ups, and at the start of the novel, all Calli wants is to make a lasting friendship.

Calli meets Jinsong, her neighbor, who shares her fascination with astronomy. Calli’s budding friendship with Jinsong conflicts with her desire to keep her Tourette’s a secret. Calli’s classmates bully her because of her tics, and Jinsong doesn’t defend her because he is embarrassed. Tensions rise between Calli and her bullies until Calli is injured trying to suppress a tic, and she finally tells her teacher and a classmate the truth about her Tourette syndrome.