Roxton is looking for the materials for a crossbow to bag a T-Rex, but when one actually interupts him in his labors, he runs in the direction opposite his fellow travelers to keep them safe. He winds up falling into a hole that suddenly opens up. When the rest of the group search for him, they also fall into the hole, which turns out to be a whirlpool. It sucks them all under the water, and they emerge in a lake. They quickly find out that in this part of the plateau, the dominant species are lizard-like men, descendents of dinosaurs, and the humans are subservient to them. There is an ancient Roman structure to this civilization, including gladiator-type battles. While Marguerite and Veronica are forced to change into silky gowns for the entertainment of Tribune, the lizard-people's leader, Roxton is chosen to fight another human prisoner. The slaves and travelers rebel, and overthrow the lizard-men's intolerable rule, but not without loss ~ Roxton's opponent's sister ~ a rebel leade

Challenger, Malone and Veronica are searching for sulfur, in order to make more gunpowder, when they walk into a burial ground. They are attacked by warriors in black and white paint who capture Challenger. That night the group sneaks into the warriors' village...to find Challenger sitting quietly and drinking tea with a beautiful blonde woman named Cassandra. She and her husband had been part of an early expedition, also stranded and found by the warriors tribe twelve years ago; they were soon made king and queen there. She tells our group that going onto the burial grounds was considered taboo, and for this Challenger would have to remain captive for life. The only way they can save him is by going to the Cave of Fear and retrieving her husband's bones for burial. They set off, but soon discover why the cave is avoided ~ it's walls are covered in a hallucinogenic fungus, wtih a really nasty additional effect. It drives those affected to suicide - which Cassandra apparently knew when