1936: Fahnrich Peter serves on a torpedo boat. Peter loves Carmita, the pretty sister of a fellow seaman. But then his superior officer falls in love with her, too, who offers to marry Carmita and who accepts. Disappointed, Peter's relationship to his superior turns sour, but eventually improves after recognition of his heroic behaviour handling a fire on board his ship. Later on, his unit is sent off to fight in Spain against the Reds. In those same waters, Carmita and her father are taken prisoner by the Communists when they commandeer their cruise ship. Peter's commander receives the order not to take action against the Spanish communist pirates, but Peter and his buddies take it upon themselves to take the situation in hand. However, Peter and his buddies find themselves prisoners of the Commies, too and now his superior must decide what to do about it.