Planet Earth is quite simply the greatest nature/wildlife series ever produced. The ultimate portrait of our planet looks at the key factors that shape our natural history. The sun and fresh water dominate the lives of all animals and plants on Earth and trigger seasonal migrations, small and large.

The theory of Némesis, a star that orbits the Sun and causes catastrophic events is explored. Nemesis is a hypothetical red dwarf or brown dwarf, originally postulated in 1984 to be orbiting the Sun at a distance of about 95,000 AU (1.5 light-years) somewhat beyond the Oort cloud, to explain a perceived cycle of mass extinctions in the geological record, which seem to occur more often at intervals of 26 million years.

This is the story of two tiny animals coming of age. In the wild woods of North America, a young chipmunk is gathering a vital store of nuts ahead of his first winter - in his way are ruthless rivals and giant predators. In the steaming rainforest, a young tree-shrew is forced deep into the jungle to find food. She must draw on all her intelligence and agility if she is to escape the ultimate jungle predator - a reticulated python!

Farrands, Hutson, and Kasch first worked together on the documentary film His Name Was Jason. According to Farrands, who reunited with Hutson, they jointly decided that it was time to tell the stories behind why the various Elm Street films were created and why they decided to fund the entire project independently.

As almost all animal inhabitants of Antarctica are forced to migrate north, the sea underneath the frozen ice still provides a home to many specially adapted fish whose cells are protected from freezing through an 'antifreeze' liquid. Many of them feed on the faeces of other animals. The most notable larger animal that does not migrate north is perhaps the Weddell Seal, which can be found as close as 1300 kilometres to the pole. Groups of seals tear holes into the ice to dive for food and come up to breathe. The females come back to the ice to give birth. This episode also describes primitive plant life such as lichen, which can still be found on the continent in winter, even in the extremely dry and permanently frozen valleys conditions under which dead animals can lie frozen for many centuries without decomposing. It details the life of the Emperor Penguin, 'the only birds to lay their eggs directly on ice'. While other animals retreat, Emperors migrate not just to the ice, but into the Antarctic continent. The females lay eggs which are incubated by the males under the harshest conditions on Earth (huddling closely together for warmth), while the females return to the sea.

A young common chimpanzee nicknamed Oscar is part of a close-knit tribe of chimpanzees. They occupy a forest territory which is rich in native fruits, nuts, and figs, among other things. The chimps hunt small tree monkeys, and they also eat termites collected with primitive tools made from sticks. They also use rocks as tools to crack nuts. Oscar is tended by his mother, nicknamed Isha, and from her he begins learning many things about how to survive in the jungle. In the chaos of an attempted raid by a rival gang of chimpanzees led by 'Scar', Isha is injured and separated from the group and her son. This twist of fate leaves Oscar to fend for himself with a little help from an unexpected ally.