Claude Rains,Philip Dorn,Onslow Stevens 1951 During World War II, Pat Bannon's whaler sights a shell-ridden Danish four-rigger in the waters off of Newfoundland. The crew has fled and only Captain Skalder is aboard. Thinking it has been a victim of a German U-boat, Bannon agrees to tow the vessel to a small Newfoundland port, the destination of the whaler's sole passenger, Margaret McLean. During the voyage it becomes apparent that one of the whaler's crew is a Nazi agent. In port, Bannon and Conrad, a crewman who proves loyal to the Allied cause, discover the the vessel they aided is a U-boat supply ship.