A volcano's deadly gasses threatens life in Lost Valley in "The Eruption." Turok and Andar are saved by a cave tribe, and in turn they help the tribe find refuge against the choking ash by driving honkers from a sheltering cave. But honkers are not the only ones who want to occupy the cave, as a rival cave tribe tries to drive them out. Then, items are disappearing from Turok and Andar's camp at night. Andar decides to find out who or what is doing it, and is captured by "The Night People."