Police constable Dave Wong (Daniel Wu) thinks he may have committed a grave error - the dying man he just saved is none other than Hon Kong, a notorious armed robber and cop killer.

One month later, the nightmare continues for Wong when Kong, having escaped from custody, leads a group of masked gunmen - his "Gang From Hell" - in a daring downtown heist. It ends in a bloody and violent shootout, leaving a dozen policemen and passers-by dead or maimed. Wong is guilt-ridden; if he had not saved Kong's life, those innocent lives would not have been lost. He vows to redeem himself by doing everything he can to single-handedly stop Kong and his gang.