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.

The details of undercover police officers are deleted from a police database and a senior officer is left struggling to know who are the undercover officers and who are the criminals.

Stephen Chow plays a selfish yet in some places kind hearted barrister who tricks his servant in doing things for his own benefit. Eric Kot playing the servant is misguided by what he thinks is love and leaves Chow vowing that he will never need Chow’s help again in life. Shortly afterwards Kot gets into some big trouble (due to be executed) with the British and calls on Chow for help. Chow tries to help his client, but is fish out of water when he has to fight this court room case according to western rules.

Chui Chik tries to lead a quiet life as a librarian. However, he is really a former test subject for a highly secretive supersoldier project and the instructor of a special commando unit dubbed “701.” The 701 squad is used for many government missions, but after one of the agents kills a team of policemen in an uncontrollable rage, the government decides to abort the project and eliminate all the subjects. Chui Chik helped the surviving 701 agents flee the extermination attempt. Having escaped, Chui Chik went separate ways from his team. Later, he discovers that the rest of the team were responsible for a violent crime spree that was beyond the capability of the local police. He sets out to stop them, donning a disguise and using the superhero alias of “Black Mask”. Having lost the ability to feel pain due to the surgery performed on the super-soldiers by the military, Black Mask is almost invulnerable.