This episode focuses upon a clan of herbivorous Leaellynasaura as they struggle to survive in the south polar region over the course of a year. During the spring, they are shown feeding on the fresh plant growth and building nests so they can lay their eggs. A male amphibian Koolasuchus has also woken up from hibernation, heading to a river where he will stay during the summer. Out on the plains, migrating herds of herbivorous Muttaburrasaurus are also preparing for the winter. By summer, many of the Leaellynasaura clan's eggs are eaten, but those of the matriarch hatch successfully. A male Allosaur is shown hunting the Leaellynasaura and Muttaburrasaurus, but fails. The Leaellynasaura clan continue to prepare for the winter, as well as raising the young that have now grown. When autumn arrives, the Muttaburrasaurus herd soon head back north, and the Koolasuchus finds a place to hibernate through the winter. However, the male Allosaur manages to catch and kill the matriarch of the clan, and only one of the hatchlings survived. Winter finally arrives, and the forest descends into the eternal darkness that envelops the months that will go by. The Leaellynasaura clan are able to stay active, using their beaks and eyes to forage for food. During this time, the clan and other fauna use various methods of dealing with the cold such as suspended animation, hibernation or using group body temperature to maintain heat. Finally, spring returns, and two Leaellynasaura males challenge one another for the right to mate, and after a short confrontation, the clan establishes a dominant pair once again.