It was a merciless winter in the North Atlantic wastes in 1941. Convoys of vital supply ships, escorted in dangerous waters by whatever rapidly modernized warships were available, steamed from North America to England, harassed by enemy forces above and below the seas.
Ordinary Seaman Donald Cameron's life on board the destroyer Carmarthen was bound to be difficult from the start. Already dedicated a Commission and Warrant candidate at the age of nineteen, he has to face continual baiting from other members of the overcrowded lower deck, on top of the gruelling privations and vigorous watch-keeping duties in an outmoded warship. But before Cameron has been at sea more than a few weeks Carmarthen is severely damaged in a surprise daylight attack.
None of the crew, rapidly reduced by subsequent attacks on Carmarthen, is unaffected by the grim conditions of survival. The biting cold and exhaustion and the knowledge that with her engines and wireless out of action and ammunition almost expended their ship is powerless produce in the men a new bloodthirsty mood.
The prowling Focke-Wulfs and U-boats see the helpless Carmarthen as an easy target, but in spite of constant bombardment the last handful of men remain afloat, restlessly watching and waiting.... then Cameron picks out a U-boat periscope sliding fast towards the waterlogged destroyer, homing in on what appeards to be a certain victory.