An introductory page contains a diagram of the Cenozoic Era showing the Pliocene, Pleistocene, and Holocene Epochs. A brief text explains that living things have been around for billions of years and explains that Sabre-tooth Tigers became extinct about 10,000 years ago. A twenty-two page story follows which personifies a male Sabre-Tooth Tiger and takes him through a day in his life. When he hears the sounds of dire wolves, he emits a loud warning roar which gathers his pack around him. They move toward the wolves and see them across a lake. But this is not an ordinary lake.