In the last episode, Iain discovers the remarkable impact of just one plant: grass. On the savannah of South Africa he sees how grass unleashed a firestorm to fight its greatest enemy, the forests. He shows how cutting your finger on a blade of grass shows us how it transformed life in the oceans. In Senegal, he meets the cleverest chimps in the world. And, in the ruins of the oldest temple on Earth, he tells the extraordinary story of how grass triggered human civilisation.

Follow the true stories of five of the world's most celebrated yet endangered animals: chimpanzees, penguins, lions, painted wolves, and tigers. These five extraordinary animals are each engaged in a heroic struggle against rivals and the forces of nature, fighting not only for their own survival but also for the future of their dynasties. Narrated by David Attenborough.
In the first episode, we will explore the lives of a group of chimpanzees led by a male named David in Senegal, West Africa. He has already been alpha for three years - a time when leaders in this region are usually overthrown.