On the morning Letty Espinosa sets out from San Francisco for the Mexican border, her two children--fifteen-year-old Alex and six-year-old Luna--wake up alone in their little apartment on a forgotten spit of wetlands near the bay. For fourteen years, it was their grandmother who raised them while Letty worked three jobs to make ends meet. But now, her parents have returned to their home in Mexico, and when Letty fails to convince them to come back with her, she realizes she doesn"t have a choice: it"s time for her to step up and become a mother for the first time in her life. Alone and uncertain, Letty struggles to get her bearings in this new role. With Luna missing her grandparents desperately, and Alex--who is falling in love for the first time--unwilling to give her a chance, it seems impossible that she might ever be able to put her family back together again. But then she comes up with a plan that just might help them escape the abandoned neighborhoods and dangerous schools...