A disease carried by common cockroaches is killing Manhattan children. In an effort to stop the epidemic an entomologist, Susan Tyler, creates a mutant breed of insect that secretes a fluid to kill the roaches. This mutant breed was engineered to die after one generation, but three years later Susan finds out that the species has survived and evolved into a large, gruesome monster that can mimic human form.

Aspiring barber and experienced kung-fu fighter Shang learns that his childhood friend, Siu Ming, has been framed for murder by an unknown villain. When Shang begins looking into the crime, he soon finds himself the target of an assassination attempt. Who is behind all these crimes, and can Shang stop them?