In 1941, U.S. Naval Intelligence Agent Soames (John Cusack) was ordered to Shanghai to investigate the truth behind the assassination of his friend Connor. He wandered around social celebrities' cocktail parties as a reporter for the German Herald in Shanghai. He used his lover relationship with Nazi engineer Mrs. Mueller to eliminate suspicion and obtain intelligence. In a gambling game, he met Anna (Gong Li), the wife of the gang leader Lanting, and the mysterious code between the other party and his men made him curious. After failing to track him, he had to continue to inquire. In order to investigate the cause of Connor's death, he secretly met with Connor's informant. However, the meeting between the two was ruined because the Japanese army was tracking down the underground party. By chance, Soames met Anna again, and met Anthony Lanting (Chow Yun-fat), the head of the Shanghai underworld, and Colonel Tanaka (Ken Watanabe) of the Japanese Intelligence Department through her introduction. During the investigation, Soames gradually discovered that Connor's death was related to a mysterious Japanese woman (Rinko Kikuchi)...