Amazon.com description: Product Description: Follow Ari, Jenna, and Caleb as they embark on their newest time travel adventure in Terra Tempo: The Four Corners of Time. When Ari discovers a time map of the Colorado Plateau, he and the twins find themselves on a fast paced journey from Earth s underwater beginnings to the steamy jungles and huge creatures of the creepy Cretaceous. But this time, there is more at stake than just survival. This time, they are not alone. Join the intrepid trio as they venture into prehistoric life on Earth they must find ways to protect their map and all of the precious resources that the map reveals, or the rest is prehistory!