In "The Lost Tribe," Turok and Andar find a group of cave men cut off for generations from the rest of Lost Valley. After helping a cave man being attacked by a honker, they are chased by another cave tribe to an old bridge. The other end is unseen because of mist. Having no other alternative, the cross the bridge. The cave men cut the vines holding the bridge to that side, leaving them with "No Way Back." On the other side, they find honkers like nothing they have ever seen in Lost Valley. They are captured by a cave tribe there, and discover that this part of Lost Valley is cut off. That is the reason for the different beasts here. In part two, "Across The Chasm," they find that they must all go back to the other side, because a volcano is forming in the gorge below. They must find a way to raise the bridge and cross it before they are trampled by stampeding honkers.