Tarzan is searching for the lost explorer Erich von Harben when he ends up in the middle of a conflict between the descendants of the old Romans. Erich is found by the benevolent Romans of the hidden city of Castrum Mare, where he is somewhat reluctantly named official historian. Tarzan ends up with the less sympathetic Romans of the rival city state of Castra Sanguinarius. Tarzan flees and continues the search for Erich.; Three villains intend to steal Meru's talking animals, but Meru is prepared for them. The men flee in terror when they come face to face with a fire-breathing dragon! In reality, they have been bested by Meru's science: the dragon was a 3-D projection of a small lizard and the fire was red mace.; Tarzan's first nightmare!