曾在西班牙杀过人的水手Michael O'Hara(奥逊·威尔斯 Orson Welles 饰)回到了纽约,一天夜里他在路上救了遭到打劫的美女Elsa(丽塔·海华斯 Rita Hayworth 饰),于是Elsa让她的丈夫,律师Arthur Bannister(埃弗雷特·斯隆 Everett Sloane 饰)找到Michael,让他来船上当水手。Bannister一家刚从上海回到纽约,正要坐船前往旧金山。在海上航行的时候,Michael和Elsa情愫暗生。而Michael也认识了Arthur的朋友George Grisby(Glenn Anders 饰)。George知道Michael曾经杀过人后,想让Michael再杀一个人,并承诺给他五千美元的佣金,而他想让Michael杀的人,就是George自己。原来George想制造自己已经死了的假象,然...Michael O'Hara, against his better judgement, hires on as a crew member of Arthur Bannister's yacht, sailing to San Francisco. They pick up Grisby, Bannister's law partner, en route. Bannister has a wife, Rosalie, who seems to like Michael much better than she likes her husband. After they dock in Sausalito, Michael goes along with Grisby's weird plan to fake his (Grisby's) murder so he can disappear untailed. He wants the $5000 Grisby has offered, so he can run off with Rosalie. But Grisby turns up actually murdered, and Michael gets blamed for it. Somebody set him up, but it is not clear who or how. Bannister (the actual murderer?) defends Michael in court.