The expedition team, which includes specialist zoologists, explorers and the BBC crew, travels to the extinct volcano of Mount Bosavi in central Papua New Guinea to document the biodiversity of this little-visited area and search for new species.

At the time of filming, logging was taking place about 20 miles (32 km) south from the volcano, and one of expedition's aims was to find evidence to support the case to protect the area.

Some members of the expedition team travelled to the island of New Britain several hundred kilometres to the east to chart an unexplored cave system and observe an active volcano.

[1] Papua New Guinea's rainforest is currently being destroyed at the rate of 3.5% per year, and the practice of logging about 20 miles (32 km) south from the volcano presents a potential threat to the ecosystem.

[2][3] Natives of the tribe who own the forests help to make a base-camp on the outer slopes of Mount Bosavi in advance of the arrival by helicopter of film-makers and a team of experts from all over the world, including scientists from New Guinea.

On New Guinea Buchanan films a fruit-dove on a nest, Dumbacher takes blood from a king bird-of-paradise for research and reports that they have netted many more species, Allison finds more frogs, and McGavin follows a caterpillar changing into a large colourful moth using time-lapse photography.

The extinct volcano is filmed from the air as the helicopter takes an advance team onto its rim, where they have arranged to meet local Kosua people who will be their guides.

He sees a brahminy kite hunting over the grey ash-covered landscape, and finds an adult rhinoceros beetle and one of the larva in a tree stump.