This tense, no-frills British study of submarine warfare is packed with incident and period detail. Director Anthony Asquith sets the scene and establishes the characters during seven days' shore leave, before the crew members of the Sea Tiger embark on a dangerous mission to sink a Nazi battleship in the Baltic. John Mills invests his commanding officer with quiet dignity, leaving Eric Portman with the showier role as the German-speaking seaman who must try to save the day when the submarine runs out of fuel. But the movie really benefits from the little-known British character actors down the cast, whose portrayal of quiet heroism seems very credible indeed.

A gripping tale of WWII naval warfare in the Baltics, starring John Mills as Lt. Freddie Taylor, a British submarine Captain. The crew of the Sea Tiger are summoned from leave on shore with their families, and sent on a secret mission to intercept the Nazi battleship Brandenburg. In the ensuing battle the British submarine is damaged by a German destroyer. The submarine is leaking fuel so badly that the crew won't be able to make it back to Britain before running out somewhere along the Danish coast. When it seems that their only option may be to blow up the submarine and try to escape to Denmark, seaman James Hobson hatches a plan...