On a deserted beach in San Francisco, California, a tryst in the back seat of a car ends with the murder of George Wilburn. Later that morning, charges are dropped against a criminal named Hawkins because the evidence against him was obtained illegally by police inspector Harry Callahan. Although Hawkins gloats over his victory, Harry threatens continued harassment. Harry Callahan goes to the Acorn Café and orders coffee to go, unaware that a group of armed robbers are seated among the patrons. Loretta, the waitress, pours an excessive amount of sugar into the coffee, and when Harry complains, a gunfight ensues. Police surround the diner before the surviving robber can make his escape. That evening, Harry intrudes on a wedding reception hosted by Threlkis, a local crime lord. Harry blames Threlkis for the brutal murder of prostitute Linda Doker, who documented many of the mobster’s secrets. Threlkis is unfazed until Harry produces an envelope, purportedly containing those documents, and the crime lord dies of a heart attack. Afterward, Harry reveals the envelope to be filled with blank pages. In the morning, police discover George Wilburn’s body, noting that he was shot in the groin and in the head. Later that day, Harry is reprimanded by Captain Briggs and the police commissioner for the wedding incident. Harry argues that he rid the city of a major criminal while solving the Linda Doker case, even though he interfered with an undercover investigation. The commissioner describes Harry’s methods as effective, but also “costly and destructive,” and punishes him with a mandatory furlough. Meanwhile, artist Jennifer Spencer visits her catatonic sister, Elizabeth, at a mental hospital and details the murder of George Wilburn, a member of the gang that raped both sisters ten years earlier. That evening, Harry kills two of Threlkis’s henchman in self-defense. The following day, Harry is visited by Detective Horace King, who dissuades the disgruntled inspector from leaving the police force, joking that his superiors need someone to complain about. Jennifer returns to her hometown of San Paulo, California, where she has been commissioned to restore an antique carousel, but she is constantly haunted by memories of her rape. In San Francisco, Hawkins and his cronies engage in a car chase with Harry, pelting his vehicle with Molotov cocktails. Harry throws one of the firebombs back at Hawkins, who loses control of his car and drives into the bay, killing all three criminals. In the morning, Harry is sent to San Paulo to conduct a background investigation on George Wilburn, with instructions that he stay away as long as possible. Shortly after arriving, Harry witnesses an armed robbery that results in the wounding of a young policeman named Bennett. Harry commandeers a tour bus filled with senior citizens and captures the perpetrator, but San Paulo police chief Lester Jannings is unimpressed with Harry’s exploits and discourages his involvement with local police business. After checking into his hotel, Harry discovers a bulldog named Meathead, left for him as a gift from Detective Horace King. The next morning, Harry goes jogging with Meathead, and they almost collide with Jennifer, who angrily advises him to put the dog on a leash. While researching Wilburn at the police station, Harry meets Officer Bennett, who thanks the inspector for saving his life and offers his assistance. In the evening, Harry enters a bar, where a crude woman named Ray Parkins attempts to solicit free drinks. Harry reveals himself to be a policeman and asks for information on the murder victim. Ray and her friends laugh about Wilburn’s death, and Harry leaves in disgust. The next morning, Jennifer follows a man named Kruger to a secluded beach, and fires bullets into his groin and head. At the police station, Harry notices a photograph in which Ray Parkins and George Wilburn are among a group of friends, and learns the identity of the others from Bennett. When Ray Parkins hears of Kruger’s murder, she presumes Jennifer Spencer is the killer and summons Mick, the man who instigated the gang rape, back to San Paulo. Meanwhile, Harry questions Kruger’s widow and her two brothers, Eddie and Carl, but they refuse to cooperate. Harry encounters Jennifer at an outdoor café and she apologizes for her harsh tone at their previous meeting. While discussing the recent murders, she suggests the killings were motivated by revenge. Although Harry approves of revenge, he cannot condone breaking the law, and Jennifer politely ends the conversation. The next morning, Mick’s arrival in San Paulo coincides with Jennifer’s murder of Tyrone, another member of the gang. Harry discovers the body later that day, and criticizes Lester Jannings for his department’s unproductive search for the killer. That evening, Harry visits Ray Parkins, unaware that Jennifer is hiding outside. Mick threatens Harry with a gun and is placed under arrest. When the men have left, Jennifer enters the house and murders Ray. Later, Harry sees Jennifer walking along the beach and offers her a ride home. They make love, and while Jennifer sleeps, Harry searches the house and matches her car to one he noticed outside the Parkins home. Mick is released from jail and breaks into Harry’s hotel room, accompanied by Mrs. Kruger’s brothers, Carl and Eddie. They kill Detective Horace King, who intended to surprise Harry. After discovering Ray Parkins’s body, Harry confronts Mick, Carl, and Eddie, who beat him and throw him off a pier. Jennifer drives to the Jannings home and finds another of her attackers, Alby, confined to a wheelchair. Lester Jannings explains that Alby hated himself for his part in the rape and attempted suicide by driving into a retaining wall. Although Alby survived, he lives in a vegetative state. Mick, Carl, and Eddie enter the house, abduct Jennifer and kill Jannings. Harry emerges from the water, finds Horace dead in the hotel room, and loads his Smith & Wesson .44 Magnum pistol. Meanwhile, Mick, Eddie and Carl drag Jennifer to the boardwalk and beat her. Harry appears and shoots the two brothers, while Mick uses Jennifer as a human shield. He climbs onto the rollercoaster, pulling Jennifer with him until she able to break away. Harry shoots Mick, and he falls from the rollercoaster onto the carousel, where he is impaled on a wooden merry-go-round unicorn. As the coroner removes the bodies, Jennifer assumes she is under arrest. However, when police find her murder weapon on Mick’s body, Harry blames him for the killings and allows Jennifer to go free.