Prison is a dark satire exploring themes of confinement and free will. In a hall-of-mirrors Britain, malcontents are held in the ancient, city-sized penitentiary known simply as Prison. Edwin Norris, a dissatisfied showbiz reporter, tries to launch a serious career by investigating the place, only to become a captive himself. Journeying through the grotesque dominions of Prison, Edwin is subject to re-education, joins a protest that becomes a riot and narrowly escapes being tortured to death. His injuries are healed only for him to be used in a medical experiment. Later, he witnesses the prostitution of inmates, tastes prison work and prison privilege. In the course of these episodes he encounters crooks and chancers, sadistic gaolers, evil scientists, drag queens, a mysterious helper, a lover and more. As his ordeal threatens to engulf him, Edwin questions the worth of his own existence. At the last, with an amnesty within reach, he makes a discovery that forces him to decide what to make of his life.