Narrated in the first person by Moth, the verse novel's protagonist, Me (Moth) opens with Moth explaining that she was the only survivor of a car crash that killed her parents and brother. When Moth is discharged from the hospital, she goes to a mostly white Virginia suburb to live with her Aunt Jack.
Moth feels survivor's guilt and the memory of losing her entire family haunts her daily. As a junior at her high school, Moth notices that the Black students, who are in the minority, are teased by the white students. However, Moth herself is ignored by other students; she assumes they don't bully her because they know the scar on her forehead is from the accident. At home, Aunt Jack drinks heavily and refuses to discuss the accident. Moth's ambition has always been to be a ballet dancer. However, after the accident, she won't let herself dance because she associates the activity with joy. She admires her grandfather, a Hoodoo practitioner who taught her how to cast spells and make offerings to their ancestors.
Just before the end of the school year, Moth meets Sani, a half-white, half-Navajo boy who has just moved in with his mother and stepfather. Moth is immediately drawn to Sani, who is the only student to acknowledge her presence. Moth learns that Sani lives down the block from Aunt Jack. As Sani and Moth grow closer, it becomes apparent that Sani's stepfather is abusive. Sani also struggles with his mental health and takes unspecified pills to regulate his mood. Sani is a talented musician who longs to apply to the Juilliard Conservatory, but a lack of support in his dysfunctional home environment is making him second-guess his chances.
When Sani can't handle his stepfather's physical and emotional abuse any longer, he takes Moth on a cross-country road trip to Sani's father's home on the Navajo Nation reservation. The two grow closer during the trip as each opens up about their ambitions and trauma. Sani encourages Moth to dance, reminding her that the death of her family members is not her fault. Moth encourages Sani to apply to Juilliard.
At Sani's father's house, Sani's father—a traditional healer—doesn't address Moth. Moth is confused to discover a sketch in Sani's bedroom: it is a portrait of Moth with moths for hair. Sani says he saw her in a dream before. Sani's father gives Sani herbal pills to help regulate his mood alongside the unspecified blue-and-white pills. He also blames Moth for making Sani's condition worse. Moth, however, encourages Sani to take his medication consistently—something Sani resists doing.
After two weeks at Sani's father's house, Sani's father has a revelation and withdraws a photo from a drawer. The photo is of Moth as a child next to her grandfather. Sani's father becomes emotionally distraught as he explains that his own father was friends with a Hoodoo man, Moth's grandfather. Moth's grandfather predicted that Moth would one day need help on her journey to the afterlife, and he arranged for Sani—a boy with the capacity to see ghosts—to be her guide. In this climactic scene, Sani and Moth both realize that Moth has been a ghost the entire time, because she died in the car accident with her parents and brother.
After confessing their love for each other, Moth and Sani accept they must part because Moth needs to continue her journey to the afterlife. Years later, Sani becomes a famous musician. In a performance at Madison Square Garden in New York, he dedicates to Moth a performance of the song he improvised with Moth during their road trip.
