Gates searches high in the Himalayas for Shangri-La. He learns of its legend as a hidden utopia. In the most remote reaches of Nepal near the border of Tibet is an area known as the Mustang, an area that's been closed off to the outside world and the passage of time. But now Josh and his fellow archaeologists have been granted access to explore it. He finds out secrets hiding inside its sky caves, man-made chambers carved into cliff walls.