When David Innes returned from the outer world to Pellucidar, the land "At the Earth's Core," he brouight with him such implements as might aid him to establish the Empire of which he dreamed.

But David and his friend Perry were dealt unexpectedly heavy blows that set back their scheme to bring civilization to the Stone Age land. For Hooja the Sly One was quick to turn David's advantages against him, dealing the cruelest blow by the abduction of Dian the Beautiful.