In the early 1990s, tractor worker Tie Tou (played by Jackie Chan), risking his life to smuggle himself into Japan to seek refuge with his fellow villager and friend A Jie (played by Nicholas Tse), in hopes of finding his girlfriend Xiu Xiu (played by Dorothy Xu), who was studying in Japan but had lost contact. Tie Tou, like some other smuggled immigrants, does manual labor at the dockyard and also engages in illegal activities for a living, during which he becomes entangled with the local largest gang leader Jiangkou (played by Masaya Kato), gaining more and more power. Unfortunately, A Jie has long-standing frictions with the foreign gang leader Gao Jie (played by Gao Jie), which involves Tie Tou in the gang warfare; the police also name the investigation file on the foreign gang's influence as the "Shinjuku Incident", investigated by officer Kitano (played by Naoto Takenaka)...