The film follows two children in New Bedford, Massachusetts, as they spend an eventful summer at a beach house with their mother and her boyfriend. Billie, a 15-year-old girl, considers singer Billie Holiday a fairy godmother. In order to take care of her 11-year-old brother Nick, Billie has to find ways to cope with the ever-changing challenges of life. In the process, they meet another teenager and run away from home, and the three of them embark on a "runaway journey" away from their parents. They discover freedom and charm among the boats and railroad tracks in New Bedford. When they break into a mansion, they fantasize about the luxurious life and bring this atmosphere of opulence into their adventure.