Harry Morgan is the owner-operator of a charter boat in wartime Martinique. Harry is approached by Free French activist Gerard, who wants to charter Harry''s boat to smuggle in an important underground leader. Claiming to stand apart from politics, Morgan refuses. Then he meets and falls for glamorous pickpocket Marie Browning, who wants to return to the USA. In order to help her, he agrees to help Gerard, using his boat to bring a resistance fighter and his wife into Martinique.