Michelle Yeoh makes her starring role debut in this police drama\action spectacular, directed by Corey Yuen. The film opens with the fierce, relentless Inspector Ng (Yeoh) cleaning the clocks of a band of thieves. Meanwhile, vicious crime boss Tin (James Tien Chun) puts a hit out on his accountant after he tried to sell his boss out to the police.
The accountant is killed but the incriminating piece of microfilm is swiped by two-bit thugs Aspirin (Mang Hoi) and Strepsil (John Sham Kin-fun). Ng gets wind of the murder when the dead man's passport shows up on a fleeing criminal. She tracks the document to forger Panadol (played by director Tsui Hark).
Later, Chinese-speaking Scotland Yard detective Carrie Morris (Cynthia Rothrock, in her film debut) shows up and soon the two are tracking down Tin. This film spawned a series of sequels including A Serious Shock! Yes Madam!