Mabel Banner, age fifteen, is a girl on the run. Escaping a dark and tumultuous life in the foster care system in Oklahoma, she runs to Key West, where she becomes first mate on board the sailboat Stella Luna, with the amiable Jake Ennis as captain. In Florida she forges a new life with a new name and tries to forget the circumstances that brought her there. But can Mabel keep her past a secret from Jake? Will the authorities looking for her eventually catch up? And mostly, will she ever have a chance at a normal life? Mabel finds that no matter how hard she tries, she can't outrun the ghosts that haunt her dreams and the feeling that, eventually, everything she has fought so hard to gain will slip out from between her fingers like the sugar white sand of a Gulf Coast beach.