Earth, 2000 years after the holocaust which drove man deep underground; a ghostly, deserted planet peopled only by the diligent robots who, century after century, silently harvest grain which no man will eat. Up into this eerie world comes Mel, a questioning young Roamer who has disobeyed the Law which says he must never venture into or beyond the Lost Levels. Together with three companions, and a companion not of this earth, Mel takes on the awesome task of freeing human beings from the tyranny imposed upon them by their remote ancestors; of justifying the agonized cry of Barney as he died in a Forbidden Level; 'I am a man! Everything is for Man!'