Journey to secret worlds where lives are wrapped in unexpected of ways. The fifth episode of the series takes viewers into the fascinating world of forests, revealing their hidden complexities and the intricate relationships within. Initially perceived as tranquil, forests are in fact bustling with life and intricate ecological interactions. The episode showcases various species, each with its unique lifestyle and survival strategies. Highlights include the Oriental pied hornbills in Borneo, whose extraordinary nesting rituals and partner dynamics are captivating.
The Amazon rainforest is explored, introducing the peculiar treehoppers and their unique communication methods, vital for survival amidst numerous predators like ants and assassin bugs. The episode also delves into the intelligent and cooperative hunting techniques of dholes in the forests of India. The narrative takes a turn to China, focusing on the visually stunning courtship displays of Temminck's tragopans and golden pheasants. In the temperate rainforests of Western Canada, the rare spirit bear and its unique relationship with its habitat are examined.
The episode concludes with an insightful look at the impact of human activity on forests and their inhabitants, particularly focusing on chimpanzees in Uganda, whose survival is increasingly intertwined with human expansion.

The final episode begins with a description of the extreme cold conditions that characterized the beginning of the Holocene period, and how species like the bison and the wolf adapted to survive in these hostile environments. We will witness the majesty of the woolly mammoth and the fierce cave lion, with a vivid reconstruction of their struggles for survival. We'll see the impact of climate change during this period, from the expansion of the deserts to the transformation of the tropical rainforests of Africa into grasslands, deeply affecting primates and other animals. It highlights how these changes forced primates to adapt to life on the ground, facing new challenges and predators.
A crucial turn occurred with the emergence of humans as dominant predators and their influence on the extinction of large mammals. The documentary describes humanity's transition from hunter-gatherers to farmers, a change that radically altered the landscape and biodiversity of the planet. Finally, it poses a reflection on the current challenges of climate change and the sixth mass extinction, inviting viewers to consider humanity's crucial role in shaping the future of the Earth.

The rainforest is home to more species of plants and animals than any other habitat on the planet. But for humans, life there is not as easy as it looks. Life in the trees requires great skill, ingenuity and sheer bravery. The Matis of Brazil carve 4-metre-long blow-pipes to hunt monkeys - in near total silence. Deep in the Congo forests, Tete defies death by scaling a giant tree using nothing more than a liana vine, and he must then negotiate an angry swarm of bees - all to collect honey for his family. Three children from Venezuela's Piaroa tribe venture deep into the jungle to hunt tarantulas - to toast for lunch! In West Papua the Korowai tribe show-off their engineering skills by building a high-rise home 35 metres up in the tree tops. Most memorable of all, in Brazil we join a unique monitoring flight in search an un-contacted tribe...