We are in Arizona, 220 million years ago. A lone Placerias is seen feeding on the vegetation on the floor. These were some of the first dinosaurs which were destined to become a immensely successful group of animals.
We then see two Coelophysis running through the desert together. A herd of dehydrated Placerias is seen traveling through a desolate desert during a drought. This is a time ruled by dinosaurs. The beginning of the episode shows footage of future episodes. After traveling back further in time to the late Jurassic period, we reach 220 million years ago in the late Triassic. The episode begins in the present day and instantly goes back in time 65 million years to the late Cretaceous period, a time when the Himalayas did not exist and the Atlantic Ocean is only half as wide. The episode concentrates on the harsh conditions Triassic life is put through and the end of the episode emphasizes that the age of the dinosaurs has begun. This episode follows life in the late Triassic period in Arizona. It features Coelophysis, one of the first in the lineage of the dinosaurs, a pair of Thrinaxodon and their desperate struggles to stay alive and to raise a family and a female Postosuchus, a fierce predator designed only for killing.