As World War II nears its end, the small island of Hashima (nicknamed "Battleship Island") off the coast of Japan is the site of a massive coal mine, where 400 Koreans lead bleak lives as conscripted laborers. Tensions run high between the Japanese soldiers who maintain order with shocking cruelty and violence, and the Koreans from all walks of life who were tricked or forced into coming there. Then, just as the island's dark secrets are revealed, the Koreans plot a daring escape..