Amber Appleton and her mom are homeless: they live in Hello Yellow, the school bus her mom drives for a living (yes, sorta like rock stars live on buses). But this doesn't shake Amber's positive outlook on life. She still has her dog, Billy Big Boy, and her gigantic list of afterschool activities- she teaches ESL, befriends a Vietnam veteran named Private Jackson, and spreads her optimism among the elderly at a nursing home. Then Amber's unchanging attitude takes a huge blow when her mother suffers a violent tragedy. Can Amber overcome what's happened to her family?