In 1996 Los Angeles, California, a helicopter flies over the war torn city and police officer John Spartan tells the pilots that a bus with thirty passengers has been hijacked by the notorious criminal Simon Phoenix. Connected to a tandem, Spartan leaps from the helicopter onto an abandoned building and dodges a barrage of gunfire. As Spartan fights his way to get inside Phoenix’s hideout, the villain watches from a video monitor and punctures pipes of liquid gas with his knife. When Spartan confronts Phoenix, he discovers he is standing in a pool of gasoline, which Phoenix ignites with a cigarette. Although Spartan drops his gun in the flames, he subdues Phoenix in a fistfight. As he carries the villain out, the fire ignites and levels the building. Walking away from the crime scene, Spartan is berated by his superior for making the arrest without authorization and acting like a “Demolition Man,” but Spartan argues he had nothing to do with the explosion. He insists the hostages were not in the building, but when thirty bodies are found on the site, Spartan is blamed. Phoenix vows to meet up with his adversary in prison. Spartan is sentenced to seventy years in the California “Cryopen” Cryopenitentiary for involuntary manslaughter, where he is frozen and subjected to mental rehabilitation through a behavior modifying technology called “synaptic suggestion.” In 2032, Southern California has been redeveloped as the Utopian society “San Angeles” after a devastating earthquake. Lieutenant Lenina Huxley calls Cyropen warden William Smithers while driving her patrol car through the placid city and complains that her work is uneventful. Meanwhile, outside the San Angeles Police Department, rebels in an underground hideout penetrate the lawn with a device that spray paints “Life is Hell E.F.” on the building’s sign. It is immediately removed. The rebels spy on a food delivery truck with a periscope, plotting a heist so they can redistribute the provisions to hungry citizens. When Huxley arrives at the station, Chief George Earle says he was monitoring her conversation with Smithers and reprimands her for desiring “chaos and disharmony.” After cursing the chief in her office and receiving a citation for swearing, Huxley is visited by her colleague, Alfredo Garcia, who observes her collection of 20th century artifacts and says she is obsessed with the brutality of the past. Meanwhile, at the Cryopen, Phoenix is wheeled into a parole hearing and uses a password to unlock his restraints. With unbridled power, he kills the guards and extracts Smithers’s eyeball, which he uses to bypass the security retinal scanners. Back at the police station, a computer reports the events as Huxley and her fellow officers watch Smithers die on the monitor. When Huxley performs a search of inmates who had parole hearings that morning, Officer Zachary Lamb, the only officer who was on the force in the 1990s, recognizes Phoenix and explains the villain is extraordinarily evil. The computer continues to track Phoenix’s path to the parking garage and reports another murder and a stolen car. Huxley orders the computer to follow the car. Meanwhile, Phoenix accesses a public computer terminal and looks up “E. F.,” Edgar Friendly as a voice in his head commands him to kill the rebel leader. Phoenix tries to find a source of weapons but police officers surround him. Unfamiliar with making arrests, an officer awkwardly follows computerized instructions but the villain subdues the police with superhuman strength. Elsewhere, the leader and architect of San Angeles society, Dr. Raymond Cocteau, warns his council of androids about Friendly and his band of subversive “Scraps.” When Cocteau claims the Scraps have provoked terrorist acts of dissent, Associate Bob interrupts the meeting to report Phoenix’s escape. In a video call to Chief Earle, Cocteau orders him to stop Phoenix by any means necessary. Officer Lamb recalls that Phoenix only had one adversary before he was frozen, Spartan, and Huxley argues the Demolition Man is their best defense. The Chief reluctantly agrees to release him from the cryostatic freeze. As Spartan awakens, Huxley informs him of Phoenix’s escape but Spartan is resentful of his arrest and averse to take on his new mission. After catching up with Lamb, Spartan disparages society’s new austerity and argues with Earle about Phoenix's next move. When Spartan predicts Phoenix is searching for a gun, Earle says they only exist in museums. Meanwhile, at the Hall of Violence, Phoenix breaks into a gun exhibit and gathers a supply of weapons. Arriving at the museum, Spartan reunites with his rival in a protracted gunfight, but Phoenix escapes and runs into Dr. Cocteau, who reveals that he was the voice in Phoenix’s head that ordered him to kill Friendly. Phoenix runs away and the doctor pretends to be grateful to Spartan for saving his life, inviting the detective and Huxley to Taco Bell for dinner. That evening, following Cocteau's direction, Phoenix accesses the underground through a manhole. At the same time, Huxley drives Spartan to their dinner date and explains that Taco Bell is the only restaurant chain left following the franchise wars. The meal is interrupted by Friendly's troops, who fire at the restaurant and attack a food delivery truck. Spartan fights the Scraps and forces them to retreat. However, when Spartan sees they were only after food and hears Cocteau deride the Scraps as a menace to society, he expresses sympathy for their cause. Back at Cocteau’s office, the doctor is surprised by a visit from Phoenix and the villain orders him to defrost other criminals to serve as his henchmen. Meanwhile, at her apartment, Huxley propositions Spartan. Spartan agrees, but he is disconcerted to find that making love in 2032 is a ritual where partners do not have physical contact and are instead stimulated through electronic headgear. Huxley is disgusted by his suggestion that they share bodily fluids, which was prohibited by Cocteau because of its danger to society, but Spartan attempts to break the law with a kiss and she throws him out. The next morning, Spartan apologizes to Huxley and gives her a sweater he knitted himself. Asking her why he has this new skill, Spartan learns that knitting was part of his synaptic rehabilitation and becomes suspicious of Phoenix’s Cryopen training. Huxley checks Phoenix's file and discovers his rehabilitation program enhanced his expertise in violent crimes. When Huxley informs Spartan that the programs were created by Cocteau Industries, he confronts Cocteau in his office and accuses the doctor of masterminding Phoenix's training and escape. Holding Cocteau at gunpoint, Spartan warns that Phoenix will find a way to circumvent his control. Although the doctor orders Huxley to arrest Spartan, she and Officer Garcia follow him into the underground in search of Phoenix. Climbing down through a manhole, the detectives find a bustling, dirty city of multi-ethnic refugees who, contrary to Cocteau’s claims, are not hostile. After a confrontation with Friendly and his men, Spartan recognizes the rebel leader from Taco Bell, and the they share their contempt for Cocteau. When Friendly explains Cocteau is against free speech, independent thought and alternative lifestyles, Spartan informs the leader that Cocteau programmed Phoenix to kill him and stop the rebellion. Meanwhile, Phoenix briefs his henchmen, commanding them to kill Spartan and Friendly. In the ensuing ambush, their attack fails and Phoenix retreats to the surface. He steals Huxley's police car and Spartan and Huxley chase him in a 1970’s muscle car that was preserved underground and elevated to the city streets by a hydraulic lift. As Huxley catches up to Phoenix, Spartan climbs out of the car, leaps to the stolen vehicle and pries the door open. The men struggle and Phoenix reveals that the hostages in the1996 hijacking were dead before the explosion. Spartan throws Phoenix out of the car, but finds it stuck in self-drive and crashes into a fountain in front of the police station. Chief Earle his and men try to arrest Spartan but he ignores them. Friendly and the Scraps come to his aid with Garcia, who has joined their ranks, and they give him weapons. Huxley resigns from the force and joins Spartan. Meanwhile, Cocteau congratulates Phoenix for creating fear and chaos and says he will soon have the power to manifest his ideal society. Annoyed, Phoenix orders one of his henchmen to shoot Cocteau and they throw the doctor’s body into the fireplace. Huxley and Spartan are attacked by Phoenix’s men and Huxley is forced to kill for the first time to save her partner. After finding Cocteau's body, Huxley discovers that Phoenix is attempting to defrost other criminals in the Cryopen. Not wanting Huxley to risk her life, Spartan knocks her out with a stun baton before driving through the Cryopen wall with the muscle car. After a gunfight with Phoenix, the villain traps Spartan in a forklift and uses him for “target practice.” A bullet punctures a coolant hose and Spartan breaks free by freezing the machine. Spartan is knocked to the floor in a fight, but just as Phoenix swings his final blow, the detective smashes a freezing conductor. As Phoenix turns to ice, Spartan jumps back onto the forklift to save himself from the cryofreeze and kicks off Phoenix’s head. The Cryopen explodes as the Demolition Man runs from the wreckage. In the aftermath, Earle asks Spartan how society will go on without Cocteau, and Friendly suggests that anarchy would be in order. Spartan, however, says the two sides will have to compromise and Associate Bob offers to help Friendly lead the new government. When Huxley objects to being left out of their partnership in the final conflict with Phoenix, Spartan pulls her toward him for a passionate kiss and they leave the scene arm in arm.