For fourteen years, Letty Espinosa has worked three jobs around San Francisco to make ends meet while her mother raised her children -- Alex, now fifteen, and Luna, six -- in their tiny apartment on a forgotten spit of wetlands near the bay. But now Letty's parents are returning to Mexico, and Letty must step up and become a mother for the first time in her life. Navigating this new terrain is challenging for Letty, especially as Luna desperately misses her grandparents and Alex, who is falling in love with a classmate, is unwilling to give his mother a chance. Letty comes up with a plan to help the family escape the dangerous neighborhood and heartbreaking injustice that have marked their lives, but one wrong move could jeopardize everything she's worked for and her family's fragile hopes for the future.