It is Britain and we are in it’s future where we get to learn of a man named Alex DeLarge who leads one of the criminal gang in the city. His group commits all sorts of crimes, including using illegal drugs. On one evening, Alex and his crew engage in a violent attack and later they head to a writer’s home. They beat him up to the extent that he would never walk again and from there, Alex rapes the man’s wife in a disgusting way.
When they again attack a certain woman’s house, one of the crew members attacks Alex with a bottle and he is left behind unconscious to be arrested by the police.
At the police station, Alex is convicted of murder and rape and is sentenced to 14 years in prison. Fortunately, Alex learns of the certain program that any criminal can join for experimental purposes. The program also promises one’s freedom much more than he expects. Alex decides to join the program after serving two years, but the plan fails along the way