In 1933 Austrian adventurer Ladislaus Almasy discovered rock paintings in the very heart of the Sahara desert depicting big animals, rivers, lakes, and bathing people. Happening upon one of the trickiest riddles of climate history: the world's largest tropical desert much once have been a lush Garden of Eden. The film follows Almasy's trail in search of evidence from the most fascinating period of the Sahara's natural history.