When a man calling himself "the Scorpio Killer" menaces San Francisco, tough-as-nails Police Inspector "Dirty" Harry Callahan is assigned to track down the crazed psychopath.
The world is shocked by the appearance of three talking chimpanzees, who arrived mysteriously in a U.S. spacecraft. They become the toast of society, but one man believes them to be a threat to the human race.
A pair of NYPD detectives in the Narcotics Bureau stumble onto a heroin smuggling ring based in Marseilles, but stopping them and capturing their leaders proves an elusive goal.