During the Battle of the Atlantic in World War II, two equally able captains on opposing sides square off in a life-and-death game of tactical maneuvering. American Capt. Murrell (Robert Mitchum) helms the destroyer USS Haynes, while his Nazi counterpart, Von Stolberg (Curt Jurgens), commands a German U-boat. As both men follow their orders, they push their crews to greater lengths to achieve victory. Over the course of the intense battle, a respect develops among enemies.