A Clockwork Orange takes place in a futuristic city governed by a repressive, totalitarian super-State. In this society, ordinary citizens have fallen into a passive stupor of complacency, blind to the insidious growth of a rampant, violent youth culture. The protagonist of the story is Alex, a fifteen-year-old boy who narrates in a teenage slang called nadsat, which incorporates elements of Russian and Cockney English. Alex leads a small gang of teenage criminals—Dim, Pete, and Georgie—through the streets, robbing and beating men and raping women. Alex and his friends spend the rest of their time at the Korova Milkbar, an establishment that serves milk laced with drugs, and a bar called the Duke of New York.

Alex begins his narrative from the Korova, where the boys sit around drinking. When Alex and his gang leave the bar, they go on a crime spree that involves mugging, robbery, a gang fight, auto theft, breaking and entering, and rape. The last of these crimes is particularly brutal. The boys travel to the countryside with their stolen car, break into a cottage and beat up the man inside before raping his wife while making him watch. They then head back to the Korova, where they fight with each other. Alex, who loves classical music, becomes angry at Dim when Dim mocks an opera that Alex likes. Alex punches Dim in the face, which prompts the others to turn against their arrogant leader. The next time they go out, they break into an old woman’s house. She calls the police, and before Alex can get away, Dim hits him in the eye with a chain and runs away with the others. The police apprehend Alex and take him to the station, where he later learns that the woman he beat and raped during the earlier robbery has died.

Alex is sentenced to fourteen years in prison. At first, prison is difficult for him. The guards are merciless and oppressive, and several of the other prisoners want to rape him. After a few years, though, prison life becomes easier. He befriends the prison chaplain, who notices Alex’s interest in the Bible. The chaplain lets Alex read in the chapel while listening to classical music, and Alex pores over the Old Testament, delighting in the sex, drinking, and fighting he finds in its pages.

One day, after fighting with and killing a cellmate, Alex is selected as the first candidate for an experimental treatment called Ludovico’s Technique, a form of brainwashing that incorporates associative learning. After being injected with a substance that makes him dreadfully sick, the doctors force Alex to watch exceedingly violent movies. In this way, Alex comes to associate violence with the nausea and headaches he experiences from the shot. The process takes two weeks to complete, after which the mere thought of violence has the power to make Alex ill. As an unintended consequence of the treatment, Alex can no longer enjoy classical music, which he has always associated with violence. This side effect doesn’t bother the State, which considers Alex’s successful treatment a victory for law and order and plans to implement it on a large scale.

After two years in prison, Alex is released, a harmless human being incapable of vicious acts. Soon, however, Alex finds he’s not only harmless but also defenseless, as his earlier victims begin to take revenge on him. His old friend Dim and an old enemy named Billyboy are both police officers now, and they take the opportunity to settle old scores. They drive him to a field in the country, beat him, and leave him in the rain. Looking for charity, Alex wanders to a nearby cottage and knocks on the door, begging for help. The man living there lets him in and gives him food and a room for the night. Alex recognizes him from two years ago as the man whose wife he raped, but the man does not recognize Alex, who wore a mask that night. Alex learns later in the night that the man’s wife died of shock shortly after being raped.

This man, F. Alexander, is a political dissident. When he hears Alex’s story, he thinks he can use Alex to incite public outrage against the State. He and three of his colleagues develop a plan for Alex to make several public appearances. Alex, however, is tired of being exploited for other people’s schemes. He berates the men in nadsat, which arouses the suspicion of F. Alexander, who still remembers the strange language spoken by the teenagers who raped his wife. Based on F. Alexander’s suspicion, the men change their plans. They lock Alex in an apartment and blast classical music through the wall, hoping to drive Alex to suicide so they can blame the government.

Alex does, in fact, hurl himself out of an attic window, but the fall doesn’t kill him. While he lies in the hospital, unconscious, a political struggle ensues, but the current administration survives. State doctors undo Ludovico’s Technique and restore Alex’s old vicious self in exchange for Alex’s endorsement. Back to normal, Alex assembles a new gang and engages in the same behavior as he did before prison, but he soon begins to tire of a life of violence. After running into his old friend Pete, who is now married and living a normal life, Alex decides that such a life is what he wants for himself. His final thoughts are of his future son.