When Locke High School opened its doors in 1967, the residents of Watts celebrated it as a sign of the changes promised by Los Angeles. But four decades later, first-year Teach for America recruits Rachelle, Phillip, Hrag, and Taylor are greeted by a school that looks more like a prison, with bars, padlocks, and chains all over. With little training and experience, these four will be asked to produce academic gains in students who are among the most...