When a madman dubbed 'Scorpio' terrorizes San Francisco, hard-nosed cop, Harry Callahan – famous for his take-no-prisoners approach to law enforcement – is tasked with hunting down the psychopath. Harry eventually collars Scorpio in the process of rescuing a kidnap victim, only to see him walk on technicalities. Now, the maverick detective is determined to nail the maniac himself.

A dedicated women's libber and a male chauvinist cop become roommates.