A British naval officer has a brief affair with a woman in England and never knows that she bears him a son. 20 years later the boy is on a ship under his command when he is tracking a German Raider. When the boy is captured after his ship is sunk, he finds a way to slow the German's progress while a lethal hunt for him goes on.
| Actor | Role |
|---|---|
 Jeffrey HunterSignalman Andrew 'Canada' Brown | Signalman Andrew 'Canada' Brown |
 Michael RennieLt. Richard Saville | Lt. Richard Saville |
 Wendy HillerLucinda Bentley | Lucinda Bentley |
 Bernard LeePetty Officer 'Stokes' Wheatley | Petty Officer 'Stokes' Wheatley |
 Victor MaddernSignalman Willy Earnshaw | Signalman Willy Earnshaw |
 John HorsleyCommander John Willis | Commander John Willis |
 Patrick BarrCaptain Tom Ashley, HMS Amesbury | Captain Tom Ashley, HMS Amesbury |
 Robin BaileyLieutenant John Stafford, HMS Stratford | Lieutenant John Stafford, HMS Stratford |
 James DrakeNavigator (uncredited) | Navigator (uncredited) |