The narrative starts in the grotesque futuristic society governed by a totalitarian regime. Citizens are perfectly obedient and perfectly neglective, willingly oblivious to everything that happens with anyone else except themselves. This neglection gives birth to the ultra-violent movement of teenagers, young criminals lacking anything even vaguely resembling morals. They enjoy beating people to death, raping women including underage kids - also to death - stealing anything they think is valuable and drugging themselves - unfortunately not to death.
The story is told by the leader of one of such gangs named Alex. His words are difficult to understand - the gang uses almost undecipherable slang they call nadsat that includes Russian and cockney words. Alex starts from the description of the bar “Korova” (Russian for “Cow”) famous for his main cocktail: milk mixed with drugs. He and some other gang members - Peter, Georgie and Dim - are sitting there, drinking that milk and deciding what to do next for their own amusement. After getting intoxicated enough, they go to the library, beating an old professor carrying the books and destroying all his literature. They assault another gang and fight them using knives and razors, then just go anywhere, wreaking havoc and robbing people. After all they steal a car and go to the countryside. During their ride Alex notices a house they can break into and the teenagers go there. They find a couple in the house, beat the husband and force him to watch gang-raping his wife until she no longer moves. Before leaving Alex notices that the man is a writer and even reads something of his drafts. The text says something strange about people turned into clockwork oranges. The man writes that it is a terrible fate and no one and nothing is allowed to do such things to them. Alex throws the sheet away and leaves.
Then the teenagers return to “Korova” and fight each other. Dim and George are very unhappy with him as a gang leader. They think they can handle the gang better. To prove their point they start mocking Alex for his love for classical music - they think it is not cool and not manly. Alex quickly defends his music taste by his fists and wins. He leaves as a winner, but the tension in the gang still stays.
The next day Alex spends alone, having a good time, listening to the classical music and kidnapping and raping two ten-year-old girls - he later tells that rape feels better when he can listen to the music during it. Later he gathers his gang again to rob an old woman who, as he thinks, is rich. They go to the robbery, but this time the police manages to arrive before they run away. The rest of the gang deliberately leaves Alex behind to get rid of him and escape by themselves. He is caught by the policemen, brutally beaten and then told that the old woman is dead and the woman they raped the day before died of shock too.
Alex is found guilty and sentenced to the fourteen years in the prison. Now he is in the role of the victim. The guards don’t lose a single chance to beat him and the cellmates constantly try to rape him as the youngest one of them all. After several years in prison Alex gets used to it, he grows up and accepts the prison rules. He also finds someone close to a friend - the prison chaplain. Alex is intelligent enough for chaplain becoming interested in him. They make a deal: the chaplain invites Alex to the church to listen to the music and Alex reads the Bible. The teenager agrees: but he indulges in distorting chaplain’s words about love and mercy and searching the evidences of rape, violence and injustice in the Old Testament to mock the chaplain later.
Suddenly a fight starts in his cell. Alex and some of his cellmates manage to beat one of their enemies to death but when the wardens finally reach the cell, all the cellmates frame Alex as sole killer. The wardens, knowing that Alex brutally killed many people before, do not need to be convinced for too long. Alex is immediately marked as one of the most dangerous and possibly irredeemable. But suddenly instead of incarceration and extra years in prison Alex is offered another way: an experimental method of behavioral correction that takes two weeks. It is established by the Ministry of Interior as a big social experiment that, if successful, should resocialize the criminals disregarding the crime they committed. If Alex manages to pass the full course, he will be released immediately. Despite the desperate attempts of the chaplain to talk him out of it Alex agrees. He doesn’t believe in immortal soul, but does believe in freedom just after a few years instead of fourteen. He is immediately taken to the correction center and the experimental treatment called Ludovico’s Technique starts.
The idea of the technique is in forming the strong connection between pain and committing crime, so the corresponding reflex of the “reformed” individual becomes so strong and persistent that they are not able even to think about crime without excruciating pain. Alex is regularly injected with the drugs that cause incredible pain and make him feel unbearably sick, simultaneously with showing him the extremely violent movies. He isn’t able to close his eyes or turn away. Alex is tied to the chair, his eyes are kept open and even tears are wept away. The worst part for Alex is that the scientists use the classical music to enhance the perception and haste the forming of the reflex. When the “treating” is over, Alex is totally broken and totally harmless individual, who is ready to curl in the corner and cry after hearing the very word “violence”... or classical music. The doctors keep their word and Alex is released.
But, as a “reformed” person, he is not only harmless, he is totally defenceless in the world full of bastards like he was before. Everyone who was ever harmed by Alex, the former members of his gang, police officers (some of which are the former members of his gang), his rivals etc. - they all get their chance for revenge. The last straw for Alex is when he is beaten by Dim and his new friend, kidnapped and thrown away in the countryside to die. Gathering all his willpower, Alex crawls under the rain to the nearest cottage… just to understand that it is the cottage of the man they beat and his wife they raped to death.
Alex is lucky - the man who opened the door doesn’t recognize him - even drugged Alex was smart enough that time to wear a mask. He lets Alex in and treats his wounds offering him shelter. The man seems to genuinely care for him and sincerely asks Alex to tell his story. And Alex does. He is smart enough to conceal his past as a gang leader, starting right from the moment of his imprisonment. He tells about the experimental treatment and also complaints that classical music drives him mad and causes him unbearable pain as a side effect.
While talking to the man Alex learns that his name is F. Alexander and he is a political dissident. So the sheets he saw in his house when the gang broke into were not the parts of the novel - they were political manifests. Alexander knew before that government is going to strip its citizens of their free will and now he is sure that Alex is just the first of the many other test subjects. He tells Alex that the government turned him into a clockwork orange - not a person but an object, perfectly obedient and unable to defend himself or stand against his oppressors - and now the government will pull the strings in any way they want. F. Alexander depicts a pretty horrifying image of zombifying all the country that way. He also says that he is going to put an end to such experiments, so he will need Alex to appear on public several times and repeat what he told to him again.
But Alex doesn’t want to be a part of someone else’s plans. He angrily refuses, berating F. Alexander for being not better than the government and also treating him like an object, a clockwork orange, a tool in his plans. But, unfortunately for him, Alex is too angry to control himself and accidentally slips to nadsat. Now F. Alexander recognizes him - not by appearance but by the language. He wants revenge immediately, but still comes with the plan to turn this revenge to the benefit of his movement.
F. Alexander calls his associates and they transport Alex - too weak to fight back - to the apartment on top of a high building they rented for the plan. They gather in the next apartment and turn on the classical music loudly, hoping that Alex, unable to bear the pain, will jump out of the window and F. Alexander will be able to blame the government for his suicide. This will draw the attention of the press and, probably, the experiments will be suspended or outright seized. The best possible variant may result to the full-fledged rebellion against the totalitarian regime that doesn’t respect the freedom of thought.
The plan works. Alex feels so tormented by hearing the classical music that only after a few minutes he crawls to the window and throws himself out, falling from the sevenths floor.
Alex wakes up in the hospital. Miraculously, he survived, but while he was lying unconscious, lots of things happened. F. Alexander used his jump as an evidence that the government experiments on people. Somehow the existing system managed to survive that blow, but, to preserve a good image, they have to offer Alex to turn him into a violent bastard again. Of course he agrees and after another two weeks the reflex is undone.The Minister of the Interior (the man who came up with the idea of “reforming”) personally approaches him and makes a truce: Alex never talks about what happened again and the government doesn’t touch him. Alex agrees and the Minister presents him a new stereo.
Alex heals back to normal, exits the hospital and immediately gathers a new gang, consisting of Len, Rick and Bully, returning back to his violent lifestyle. Soon he learns that F. Alexander is imprisoned too and will also, probably, undergo the brainwashing. He rapes, destroys, robs and kills and, of course, listens to the classical music and the government pretends it doesn’t see him at all. But soon, to his surprise, Alex discovers that he becomes less and less interested in drugs, sex and violence. He tries to find the causes of such a change, even suspecting the government of cheating - but he is still perfectly able to be evil. He just doesn’t want to and seems no reasons to continue.
One day Alex meets his old friend Pete, who also used to talk nadsat and wreak havoc. But now Pete is one of those they despised - a family man and law-abiding citizen. To his shock Alex doesn’t feel repulsion towards him. On the contrary, the thoughts about family life becomes so appealing to him that Alex even thinks about raising his own baby boy. He leaves, deciding to make steps towards the peaceful adult married life, like others live. So, in the end he doesn’t even need a special experimental treatment to become just like any other citizen, he just grows up and becomes an adult.