The explorer tracks down some of the most endangered animals on the planet in their natural habitats, starting with orangutans in the rainforests of Borneo. Deforestation and poaching have halved the apes' population in the last 60 years, and they're in serious danger of becoming extinct. In the company of indigenous guides and naturalists, he gets a better understanding of how they are surviving against worsening odds caused by the increasing threat of human activity and climate change.