The Kogi once traded with Maya and Aztecs. Their civilization still survives hidden on Colombia's highest mountain. They believe they are guardians of the world. Their leaders are trained from infancy in darkness to work by connecting with 'aluna', a cosmic consciousness. They perceive 'black lines' that connect special sites essential to life. In 1990, convinced that we were destroying the earth, they sent a warning through a British film-maker and then withdrew. They have now concluded that we cannot have grasped the warning and they have to explain it better if the world is to survive. So they recalled the film-maker and instructed him to film their demonstration of these connections, using 400km of gold thread. So begins a truly bizarre journey. We see people who have no wheel or writing, who know nothing of our world, seriously discussing dark energy with a leading astronomer and correctly identifying objects seen by the Hubble telescope. But as the journey gets under way they ...