Since 1970, inmates at California's Chino State Prison have had the rare opportunity to train to become deep-sea divers, a process that is harrowing but fulfilling. Barbara Liebovitz documents the training, which lasts 10 months and involves demanding calisthenics as well as the study of such subjects as physics and medicine. Not everyone makes it to the end; only 13 inmates succeed out of 45. Liebovitz focuses on four graduates, capturing their efforts during and after their time in prison.