In 1942, when the German troops are preparing to seize
Murmansk, the Soviet command decides to intensify the activities of the Northern Fleet. The crew of the submarine 'Щ-721' performs the task of destroying enemy transport with soldiers and ammunition. The submarine of Strogov is considered to be lucky. The crew under his leadership works wonders and gets out of difficult situations. Also, Strogov is developing a tactic of a non-referential torpedo attack in spite of the skepticism of his colleagues and leadership. During the execution of the combat mission, Strogov has to take on board the boat the evacuated crew of another Soviet submarine.
Fascists lead a long pursuit after the submarine. In the end, it finds itself in an almost desperate situation - at the bottom of the sea almost without
oxygen. Commander Aleksei Strogov manages to save the boat and crew, paying for it with his life ... ==Cast==