On a mission to protect a scientist who has stolen a copy of the smallpox virus, Sean (Andy On) betrays his team of police officers in order to get the virus so he can mutate it into a biological weapon, develop a vaccine and sell it to a corrupt pharmaceutical company. The failed mission leaves Jon Man (Jay Chou) injured and his girlfriend Ice (Bai Bing) dead. With two weeks to live, he decides to spend his remaining days with his mother (Elaine Jin) who tells him that he has a long lost brother, Man Yeung (Nicholas Tse) whom she left behind with his father, Man Tin (Liu Kai Chi). Jon decides to track Yeung down in Malaysia but upon arrival, he discovers that Yeung has become a wanted felon and is part of the plot orchestrated by Sean. Jon is drawn into the conflict, not only to protect his family but to ensure his brother does not go further down the road of unrighteousness and to take down Sean's operation for good.