During the early days of the United States' involvement in World War II, an international convoy of 37 Allied ships, led by Lieutenant Commander Ernest Krause, crosses the treacherous North Atlantic while being hotly pursued by wolf packs of German U-boats. The film focuses on Krause, a career officer who was finally given command of a destroyer, USS KEELING (radio code named 'Greyhound')'. Unlike the prototypical hero, he must battle his own self-doubts and personal demons to be an effective leader of the defenders.