Primatologist Dr Julie Anderson and writer and adventurer Guy Grieve scale new heights as they explore one of the most inaccessible habitats on Earth in search of an elusive monkey.

Their home for six weeks is a specially constructed tree-house, high above Gabon's rainforest floor. It's a safe haven from the hippos, crocodiles, forest buffaloes and elephants who roam the forest.

From her precarious perch, Julie aims to study the rare, red-capped mangabey monkeys. Guy's task is to keep house by utilising all his survival experience - from digging the latrine to fishing for food and constructing a rainwater harvesting device.

Wildlife cameraman Gavin Thurston, a veteran of numerous David Attenborough series, is also on hand to capture the incredible variety of animal action and observe Julie and Guy as they adjust to their new treetop habitat.

They quickly discover that life in the jungle is a huge challenge when, on the first night, Guy discovers a huge, venomous centipede crawling beside his bed. And, on the forest floor, Gavin draws on all his filming experience when he is charged by an elephant.

Despite the hardships, Julie's dogged determination pays off. After days of tracking the mangabeys, she locates their main feeding zone and with a thermal imaging camera captures the first ever footage of the species sleeping in the wild.