Mobsters are smuggling guns into Hong Kong. The police orchestrate a raid at a teahouse where the ace detective loses his partner. Meanwhile, the two main gun smugglers are having a war over territoriality, and a young new gun is enlisted to wipe out informants and overcome barriers to growth. The detective, acting from inside sources gets closer to the ring leaders, and eventually must work directly with the inside man.

    Tequila is a "hard boiled" cop who loses his partner in a shoot-out with gun smugglers. In order to bring down the gun smugglers, Tequila must team up with an undercover cop named Tony, who goes undercover as a hired gun with a Hong Kong Triad, which is run by a vicious boss named Johnny Wong.

    A hard-boiled Hong Kong detective (Chow Yun-Fat) who lost his partner in a gunfight teams up with an undercover cop (Tony Leung) in a powerful mob to stop the mob smuggling guns and killing innocent people.