While looking for a way off the plateau, Roxton, Malone, and Challenger are saved by three Amazon women from an attack by a vicious flock of pterodactyls. Invited back to their camp, they find there are no men or boys, yet they are welcomed with open arms. While the Amazons celebrate by the light of a full moon, the men happily learn that it's breeding time -- and they have been chosen as studs. By the time they realize they will die as soon as they have served their purpose, it's too late to save themselves.