A future society of sophisticated technology in a subterranean city. Each individual has a number, not a name. Human responses and inclinations are suppressed by constant surveillance, robot policeman, and a diet of tranquiliser drugs. A couple break the rules, conceive a child and are put in prison where they meet a man who claims to know an escape route. Starring Robert Duvall, Donald Pleasence and Maggie McOmie.