Eastern Dragon Film Co.

In this prequel to Mou gaan dou (2002), Chan Wing Yan has just become an undercover cop in the triads while Lau Kin Ming joins the police force. Both the triads and the police find an enemy in a rival crime boss.

Months after the events of the original film, Ming suspects a police superintendent as being a new mole for the triads, while years earlier, Yan embarks on his first mission.