The crew of an American submarine are on a reconnaissance mission, photographing Japanese installations through a periscope camera. When attacked by the Japanese (with similarities to ) the submarine is scuttled and the crew is captured. Tortured by the Japanese, with the help of British and Australian prisoners the submarine's officers make an escape bid to get their information to the Allies. The film ends with footage of the Battle of the Coral Sea (1942), which according to the film was made possible through the information brought back by the submariners.