On the remote equatorial island of St. Jean, under cover of darkness, fugitive criminal Joe Morgan and his confederate, Spike, make adjustments to a torpedo. Later, a German submarine pulls into a deserted cove and buys six of the torpedoes. Joe then instructs them to pass through the island's protective reef within the hour. In the morning, while Joe and Spike are fishing aboard their boat, the Yankee Doodle , they discover a man swimming beyond the reef. When they take him aboard, they learn that he is the only survivor of a torpedo attack on his Merchant Marine vessel. Joe soon recognizes him as James Taggert, a former New York policeman. Taggert, in turn, remembers Joe as a man accused of murder. When Taggert suggests that Joe clear his name and join the Army, Joe replies that he has his own brand of patriotism and warns Taggert to stay away from him. On St. Jean, Joe takes Taggert to the local inn, the Halfway House, which is run by Styx, his wife Angela and his daughter Maria, and Joe gives Styx enough money to pay Taggert's expenses. Taggert meets two other European residents, the British Cavanaugh and the Austrian Kroll. Also at the inn is a group of women entertainers whom Joe has promised to transport to Brazil in the Yankee Doodle . When the women complain that Joe has again postponed their departure, he surreptitiously hands Styx enough money to increase their salaries as consolation. Later, Joe joins Judy Pierson, one of the entertainers, and tells her that he will take them away from St. Jean, but begs her not to ask him any questions. From Maria, who is in love with Joe, Taggert learns that periodically Joe pays for a big party at the inn, which is attended by everyone on the island. Taggert becomes suspicious when Maria adds that Joe always arrives late to the party. When Joe finally arrives, he passes his tobacco pouch to Kroll, who slips in some money as payment for the torpedoes. That night, Taggert searches Joe's home and discovers some Nazi insignia. He takes one of the medals, but after leaving Joe's, Taggert is hit on the head and the insignia is stolen. Some time later, Maria, who is wearing the medal, buys perfume from Kroll's store. When Kroll, who is an undercover Nazi, notices the insignia, he demands to know where she got it. She reveals that Felipo, the native man who is in love with her, gave it to her as a present, and Kroll then trades her perfume for the medal. One night, during another party at the Halfway House, Taggert, Cavanaugh and Felipo all spy on Joe and Spike while they sell some torpedoes to another Nazi U-boat. When the Germans inform him that they will not be sending more submarines for at least three weeks, Joe decides that the time is right to leave St. Jean with the women. He is stopped, however, by Kroll, who has learned from Felipo that Joe has been fixing the torpedoes so that they will blow up the U-boats. Kroll shoots Joe and is shot in turn by Taggert. Before he dies, Joe asks Taggert to take the women off the island, and Taggert agrees, finally understanding that Joe did indeed have his own brand of patriotism.