Amber Appleton, Auli'i Cravalho, is a high school senior in Portland who lives with her mother Becky, Justina Machado. After Becky's boyfriend Oliver becomes abusive, they become temporarily homeless and end up sleeping in the school bus Amber drives.
Amber stays busy with a wide range of commitments, including volunteer teaching an ESL class and working at an old age home, where she has bonded with Joan, Carol Burnett, a resident who becomes a steady source of support. She also plans an annual school variety show to raise money for charity, turning her energy toward helping others even as her own situation grows tougher.
Amber is invited to audition for Carnegie Mellon University, her deceased father's alma mater. With Becky's encouragement, she spends money they had been saving for rent on the flight, chasing a dream that could change both of their lives.
Things unravel when Becky is fired after it’s discovered they’ve been living in the bus. Becky decides to return to Oliver, but Amber refuses to join her. The night ends with Amber sleeping on a park bench and subsequently being robbed, a sobering turn that heightens the stakes of her upcoming audition.
Confiding in her friend Ty, Rhenzy Feliz, he takes Amber to his family’s vacation house to help her prepare. She opens up about how her father’s death strained their finances and how Becky—an alcoholic—frequently relapses while with Oliver, clouding Amber’s path with fear and uncertainty.
With the help of Donna, Judy Reyes, the mother of her friend Ricky Anthony Jacques, Amber tells Becky that she does not feel safe living with Oliver. They have a heated argument; Becky leaves, and Amber stays with Donna for a time. The following morning, Amber learns from the police that Becky and Oliver were killed in a drunk-driving car accident, a crushing blow that reshapes Amber’s future.
On the day of her audition, Amber discovers that her dog Bobby is sick and needs an expensive surgery. She drops out and begins working full-time to pay for the procedure, sacrificing a new chance at Pittsburgh and losing touch with the friends who once supported her. Ty confronts her, accusing her of shutting people out, and they stop speaking.
Amber plans to skip the variety show, but Ty arrives at her workplace to reveal a different plan: the proceeds will go toward Bobby’s surgery. In a powerful testament to their community, all of Amber’s friends perform in the show, including the students from her ESL class. The fundraiser remains short by $2,000, but an anonymous donation of $200,000 arrives, turning the night into a turning point.
At home, Joan reveals that she is the donor, choosing to see Amber as family. Amber is given another shot at Carnegie Mellon, and as she prepares to leave, she and Ty share a quiet kiss, a hopeful moment that signals a new chapter beginning to unfold.
