The waste produced by the chemical plant under Fahrenheit Enterprises polluted the nearby fishery. The head of the fishery, Han (Deanie Ip), applied to the court for an injunction to stop the factory from continuing production. In order to resolve the trouble, Fahrenheit Enterprises invited lawyer Ah Lung (Jackie Chan) to handle the case and authorized him to acquire the fishery. Ah Lung asked his good friends Wong Fei-hung (Sammo Hung) and Ah Biao (Yuen Biao) for help. One of them is highly skilled in martial arts, and the other is agile but not very smart. Ah Biao installed a bugging device in the fishery, while Wong Fei-hung tried every means to get close to Han and urged her to sell the fishery. Han also asked her cousin Mei Ling (Pauline Yeung) for help. When Ah Lung first met Mei Ling, he was deeply attracted to her. Soon the two fell in love, and the feelings between Wong Fei-hung and Han also became stronger. Ah Biao accidentally revealed the original intention of the three people, which disappointed Ah Hung and Mei Ling and broke up with Ah Lung and Wong Fei-hung respectively. This incident prompted Ah Lung and his gang to discover the secrets hidden by the factory.