"The Painted Mystery" of a bison drawn in a cave causes Turok and Andar to search for the people who painted it to learn of how the creature got into Lost Valley. In part one, "Secret of the Cave," they are unsure of whether to believe the animal was ever actually there, until they find proof: a single bison horn. Then, in part two, "When The Earth Shook," they meet the tribe who made the drawing in the cave, and the medicine man who wears a buffalo hide. The catch: all strangers are their enemies.