Hotheaded cop Bill Chu gets relegated to the Emergency Unit after a dustup with his inept boss. When the mob kills Chu's pal and ex-colleague during a turf-war hit, he rounds up his motley department cohorts and embarks on a mission of revenge against the gangsters.

Four young officers of the Hong Kong Police are joined together to fight against organised crime using all possible means, even if this would lead them to break the law… Their first assignment is to eliminate a gang of criminals who have stolen a shipload of explosives.

For never-do-well compulsive gambler Fong, there's only one thing more fearsome than debtors at his doorstep - having to coax a crying baby. But what if the baby becomes his golden goose to fend off his debtors? Can he overcome his phobia of diapers, milk bottles, and cloying lullabies?

When the Ronin Gang robs an armored car, three cops — Chan, Fong and Wai — go on the warpath. Each has a personal interest in bringing down Ronin leader Tien: he killed Chan's fiancée, humiliated Fong and kidnapped Wai's brother.