When Aida Hernandez was born in 1987 in Agua Prieta, Mexico, the nearby U.S. border was little more than a worn-down fence. Eight years later, Aida's mother took her and her siblings to live in Douglas, Arizona. By then, the border had become one of the most heavily policed sites in America. Undocumented, Aida fought to make her way. She learned English, watched Friends , and, after having a baby at sixteen, dreamed of teaching dance and moving with...