Shanghai, October 1941. Posing as a journalist, US spy Paul Soames (John Cusack) arrives in Shanghai from his last posting in Berlin. The city is divided into sectors controlled separately by the British & Americans, the French, and the Japanese, with the last also controlling the rest of China. When his best friend (and fellow spy) Connor (Jeffrey Dean Morgan) is found murdered - and Connor's Japanese girlfriend Sumiko (Kikuchi Rinko) disappears - Soames vows to find the killer. He learns Connor was investigating Shanghai mobster Anthony Lan-Ting (Chow Yun-fat), who works for the Germans and Japanese, especially Japanese intelligence chief Captain Tanaka (Ken Watanabe). He also gets to know Lan-Ting's wife Anna (Gong Li), Connor's undercover Japanese contact Kita (Ben Wong) and German spy Leni Mueller (Franka Potente), all of whom may have info about Connor's murder. He then finds out Connor was also investigating Tanaka and had made a discovery that involved Nazi Germany.