In October 1942, the Lisbon Maru, a Japanese transport ship secretly carrying over 1,800 British prisoners of war, was torpedoed off the coast of China by an American submarine unaware of its human cargo. Through rare archival footage, survivor testimonies, and expert interviews, this poignant documentary uncovers the harrowing journey of the prisoners as the ship began to sink, leaving them trapped below deck. The film also highlights local Chinese fishermen who risked their lives to rescue as many prisoners as they could.