The search for a way out of Lost Valley is hindered by a giant lake in "Scourge of the Sea Serpents." Turok and Andar find they must now cross it and brave the vicious sea monsters that inhabit it. Then, in "Guardian of the Pit," a cave man witnesses the two Indians killing an immense Tyrannosaurus with their poison arrows. He and his tribe try to trick them into ridding them of a marauding ankylosaurus, which dwells in a cave that they covet.