Michael Chao (Conan Lee), young and agile, was a new recruit in the police force. Francis Lee (Chow Yun Fat), an experienced cop, was lazy and frivolous in character. They were assigned to work on a murder case. Because of some misunderstanding and clash of personalities, the two were caught in a series of hilarious situations. They shadowed their suspect Donna (Li Chi), who was the cousin of a heroin dealer namely Ping. When they were to arrest both, Ping shot them and escaped leaving Donna behind. However, Donna refused to disclose any thing in the police station. Francis used his tricks to win Donna's affection in order to obtain information from her... (Joy Sales)