The series sets out to reveal the true nature of our planet in this episode, Prof. Aubrey Manning travels the globe in search of clues to the story of Earth's climate. In the Swiss Alps, Barbados, South Africa, Greenland and the bottom of the Atlantic he finds evidence that throughout Earth history there have been dramatic swings from hot to cold conditions and back again. The reason lies in the complex interactions between the rocks of the planetis crust, the atmosphere and living being.