On the long voyage home from the West Indies to Baltimore and then to England, the British tramp steamer the Glencairn takes aboard a cargo of munitions, a circumstance which turns the natural complaining of the crew into a case of genuine fear. Those fears are realized when a heavy gale tests the mettle of the ship and in the storm, mountainous waves hurtle the sailor Yank to the seething deck, thus bringing him to his death as his shipmates, Ole Olson and Driscoll, watch helplessly. As they approach land, the crew begins to suspect their brooding, aloof shipmate, Smitty, of sending signals to the Nazis, but they discover that Smitty has really withdrawn in disgrace from his family and all those around him because of his alchoholism. This revelation forces Smitty to resolve to return to his wife and children, but the reunion is tragically doomed when a Nazi plane swoops down from the skies off England and Smitty is killed in the attack. Safely in port after their harrowing crossing, the crew channel their energies into making sure that Ole leaves the sea to return to his aged mother in Sweden, but after bidding his friends farewell, Ole is shanghaied aboard the Amindra . Rescued by Driscoll and his other mates, Ole's voyage ends happily. Not so for Driscoll, because in the rescue he is taken prisoner and sails off aboard the Amindra in Ole's place. As the remaining seafarers return to the Glencairn to resume their long journey, they learn that Driscoll perished aboard the Amindra when the ship was sunk by a torpedo.