Kidstuff (Sammo Hung) has been asked by police superintendent Walter Tso (Cho Tat-wah) to investigate a case of international ammunition trade between two gangs. One of the gangs is the Japanese Yakuza in possession of stolen diamonds, and the other is a group of terrorists with a stockpile of ammunition. Whilst visiting the police station, Kidtuff meets Quito (Sylvia Chang), an old friend from when they were in the orphanage. As they embrace each other in a friendly hug, some passing police officers get the wrong idea and decide to tell her husband, Albert (Karl Maka). Albert refuses to listen to Quito and attempts to fight Kidstuff. Later, when Kidstuff and Quito decide to dine together, Albert secretly hides under their table.
Hong Kong Police Supt. Walter Tso arrests Big Dai, the reformed leader of a criminal corporation. When Dai asked his brother Richard Mao to turn himself into the police, he betrays him and decides to take over the corporation. Dai is imprisoned and an informant is murdered by one of Mao's men. With no evidence against Mao and the corporation, Tso coerced four of the "Five Lucky Stars" to go undercover in the prison, rescue Dai, and help nab Mao and bring down the corporation.
The Lucky Stars go on an island vacation and discover a nympho ghost in a castle near their cabin. Four policewomen come to investigate and the boys try to put the moves on them. After many failed attempts, one of the policewomen, Lai Ti, is possessed by a male ghost that is residing in the castle. The gang take her back to Hong Kong where they learn that the ghost wants revenge for his death. The gang are more than willing to oblige if the ghost helps them cheat in gambling. This all leads to the inevitable showdown where Kidstuff uses his kung fu skills to fight the ghost's killers.
During an international gambling competition, "The King of Gamblers" Lui Tin (Chen Kuan-tai) lost to the lascivious, psychotic lesbian queen of gamblers Sheung-kung Fei-fa aka "The Gambling Flower" (Kung Suet-fa) which caused him to commit suicide. His daughter Wai-lam (Fung Sau-yin) vows to avenge her father's death and get help from her late father's good friend. Uncle Wah (Cho Tat-wah), who is a police inspector. Wah also enlists the "Lucky Stars" to assist him.
