Action superstar Chow Yun-Fat is John Lee, whose violent past as a professional killer brings him only remorse, but also makes him the ideal assassin. In exchange for his family's safety, Lee is forced to take a job with powerful underworld crime boss Mr Wei, who wants to settle a deadly vendetta against police detective Stan Zedkov (Michael Rooker). The assignment, however, is so unspeakable that Lee would rather brave Wei's vengeance than go through with it. With the aid of document forger Meg Coburn (Mira Sorvino), who in helping him becomes an unwitting target herself, Lee races against time to outrun and outsmart Wei's army of killers.