World War II, in a British disciplinary camp located in the Libyan desert, prisoners are persecuted by Staff Sergeant Williams (Ian Hendry), who made them climb again and again, under the heavy sun, an artificial hill built right in the middle of the camp. Harris (Ian Bannen) is a more human and compassionate guard, but the chief, R.S.M. Wilson (Harry Andrews), refuses to disown his subordinate Williams. One day, five new prisoners arrive. Each of them will deal in a different way with the authority and Williams' ferocity.