Under the trackless sands of the Sahara lies Zanthodon. That vast subterranean realm is the final homeland of the one-time masters of the world's surface - great dinosaurs, mighty jungles, and the living bands of primitive peoples from Neanderthals to Ancient Minoans and even Barbary Pirates! It was into the cruel hands of those feared corsairs that Eric Carstairs' beloved cave-maiden, Darya the Cro-Magnon princess, had fallen. It was his mission to save her, as well as to keep his caveman friends and his professor guide from the innumerable dangers spawned in the unmapped wilds of the Underground World.