Louis Koo plays an assassin who wants to go straight after getting out of prison, so he turns down a job from his former employer Simon Yam to kill a politician. Yam carries out the hit himself and manages to frame Koo for the crime, who then must run from both the cops and criminals as he tries to clear his name.

After robbing countless Hong Kong jewelery shops, Ye Kuan (Simon Yam) sets out on a murderous rampage killing everything in his path. Police informants, criminals and members of the public — nobody is safe from the Hong Kong Thug.