A nightclub girl, MEI's, dead body was found at her own apartment. The police finds an obscene video-cassette tape. Unexpectedly, the male protagonist is Inspector FUNG's husband, LAI. The coroner's report shows that MEI’s rib were chopped, her back was shot an her head was hit by something hard and causes a crush at her head bone. Moreover, she was being poisoned. LAI disappears. The murder weapon got LAI’s finger-print. However, there is also a left-hand finger-print belonged to another people. YUNG finds the mamasan for more information. He then knows that MEI always went out with a drug addict, TSUEN. They even set plot to trick the nightclub customers. Later, MEI was sacked. TSUEN was chopped to death by his debtors. MEI then becomes very rich.

LAI backs to Hong Kong from Macau. He is soon being arrested. His testimony states that he met MEI who claimed that she was sick. She begged LAI to take her home. Unexpectedly, MEI puts some pill on LAI's coffee in a restaurant. She even arranged to have an affair with LAI. She then extorted two hundred thousand from LAI. LAI was so shocked that he hit MEI with a copper statue and left. LAI claims that he then wandered around in the street after this incident. Therefore, he does not have any time witness. LAI is then being detained. The police finds three more obscene video-cassette tapes at MEI’s safe-box at a bank. They arrest those three victims, FU, MING and Hei. They all got witness to prove their innocence.

The police suspects the three are in league. The police then arranges the three to stay alone. However, they eventually find out that they really do not know one another. The police discovers that HEI's wife was scratched by somebody. Simultaneously, the victim also got some skin fibre. The report proves that the skin fibre matches HEI’s wife's skin fibre. The police follow HEI’s wife. Unexpectedly, the police finds that HEI's wife is meeting FU and MING’s wives. The police immediately arrests them. The police also knows that a chemical factory has sold some poison to HEI’s wife. The three have no more excuse. They disclose the truth as well as their grievance. The victim not only extorted money from them, she even insulted the three defendants. The three defendants eventually could not controlled their temper and attacked the victim with a poisoned needle, a knife and a pistol.