In a parlay with the Mahars David bargains for information of his love Dian and his enemy Hooja the Sly One, which his foes agree to supply in return for the book containing the Great Secret of Mahar reproduction that David stole and hid in the previous novel. David undertakes to recover it, only to find that Hooja has been there before him and claimed Dian as his own reward of the Mahars!
Now he has to track down and defeat the sly one before resuming the human war of independence. Ultimately this is accomplished, and with the aid of the resources David has brought from the surface world he and Abner succeed in building a confederacy of human tribes into an "Empire of Pellucidar" that wipes out the Mahar cities and establishes a new human civilization in their place.