The film explores the eye-opening realm of these creatures to better understand how they evolved. Travelling from the rain forests of French Guiana to the Arctic Ocean, scientists use traditional and cutting edge techniques to examine both modern insects and the fossil record in their search for a single common insect ancestor. Insects are vital to life on our planet, yet almost 40% of known species are in danger of extinction.
Insects are the most diverse group of organisms on Earth. The true number of species is unknown, but some estimates suggest that only a fraction have been identified. They have successfully adapted to every ecosystem on our planet. But insects still harbour many mysteries. Where do they come from? When did they first appear on Earth? How and why have they diversified and multiplied so successfully? At a time when certain insect species are in danger of extinction and there is greater interest in their role within ecosystems, this is the fascinating story of their origins.

The fourth episode plunges us into the heart of the jungle for an exciting story of power, politics, and survival. Days after a fierce battle with Western rivals, Jackson, the alpha male, grapples with the aftermath of his injuries. The strength of an alpha is paramount, and physical frailty can quickly translate into political vulnerability. While Jackson's allies waver, Abrams and Wilson see a golden opportunity to seize control.
As Abrams makes strategic moves against Jackson, the forest resonates with news of the ongoing power struggle, attracting the attention of external threats. Battles for leadership are perilous, with uncertain outcomes for both the reigning alpha and the ambitious challenger. This episode promises an intriguing exploration of chimpanzee society and their relentless pursuit of dominance.

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...