Li Jie (Jet Li), an explosives expert, once misjudged a mission and witnessed his wife and children being blown to death. He was heartbroken and resigned from his public office. While looking for the murderer who killed his wife and children, he changed his name to Dadan and served as a bodyguard and stand-in for the superstar Long Wei (Jacky Cheung), performing desperate scenes for him from time to time. Apart from remembering the murderer's voice, there are no other clues. TV host Le Huizhen (Chingmy Yau) is suspicious of Long Wei's performance, so she follows him day and night. Long Wei was invited to participate in a large jewelry exhibition. The gangster who claimed to be a doctor (Wang Xiao) was planning to steal the diamonds at the exhibition and sent his assistant Zhu Fei (Chow Ka Ling) to sneak into the hotel as a public relations undercover. On the day of the diamond exhibition, Li Jie escorted Long Wei to the venue and left. On the way home, he accidentally recognized the doctor's voice in the car, so he desperately returned to chase the gangster, performing a life-and-death melee...