Andrew Lau

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.

2003 Hong Kong crime thriller film directed by Andrew Lau and Alan Mak. 

From the director of Infernal Affairs comes this martial arts war epic about a covert group of Qing Dynasty street-hoods-turned-assassins fighting for the Emperor, masters of the deadly, titular weapon.