Plot
Paul Kersey is a middle-aged architect who lives in Manhattan with his wife, Joanna. Their adult daughter, Carol, and her husband, Jack Toby, live nearby. One day, Joanna and Carol are followed home from the grocery store by three muggers who invade the Kersey apartment. Discovering that the women only have $7, the goons severely beat and slash Joanna and sexually assault Carol before fleeing. At the hospital, Joanna dies from her injuries. After her funeral, Paul has an encounter with a mugger and fights back with a homemade weapon, causing the mugger to run away. Paul is left shaken and energized by the encounter.
A few days later, Paul's boss, Henry Ives, sends him to Tucson to work with real estate developer Ames Jainchill, a client with a residential development project. Ames is impressed with Paul's pistol marksmanship at the target range. Paul reveals that he was a conscientious objector during the Korean War, serving as a combat medic. He helps Ames plan his residential housing development. After a couple of weeks, Ames drives Paul back to Tucson Airport and places a gift into Paul's checked luggage.
In Manhattan, Paul learns that Carol is catatonic, and an elective mute, refusing to speak to Jack. With Paul's support, Jack commits Carol to a mental rehabilitation institute. At home, Paul opens Ames' gift to discover that it is a Colt .32 revolver with a box of ammunition. He loads the gun, takes a late-night walk, and is mugged at gunpoint, but he fatally shoots the mugger. Over the next several weeks, Paul walks through the city looking for criminals, killing several muggers by luring them into a confrontation or when he sees them attacking innocent people. Police Inspector Frank Ochoa investigates the vigilante killings. His department narrows it down to a list of men who have had a family member recently killed by muggers or are war veterans.
Paul visits Carol at the institute, where she remains depressed and unable to speak to Jack or show him any affection. Ochoa soon suspects Paul and is about to make an arrest when District Attorney Peters intervenes. Peters and Police Commissioner Dryer do not want the statistics to get out that Paul's vigilantism has led to a drastic decrease in street crime. They fear that if that information becomes public, the city will descend into vigilante chaos. If Paul is arrested, he can be labeled a martyr, and people will copy his example. Ochoa reluctantly relents and opts for "scaring him off" instead. One night, Paul shoots two more muggers before being wounded in the leg by a third. He pursues the mugger and corners him at a warehouse, where he proposes a fast draw contest, only to faint because of blood loss while the mugger escapes.
Patrolman Officer Jackson Reilly discovers Paul's gun and hands it to Ochoa, who orders him to forget that he found it. At a local hospital, Ochoa visits Paul, who is recovering. Ochoa offers to dispose of the revolver in exchange for Paul's permanent exile from New York. Paul takes the deal, and his company agrees to transfer him to Chicago. He arrives in Chicago Union Station by train. Being greeted by company representative Fred Brown, he notices hoodlums harassing a young woman. He excuses himself and helps her. As the hoodlums mock him, Paul smiles while making a finger gun gesture at them, implying his vigilantism will continue.
