The ruins of Chan Chan, the greatest ancient city in the Americas, lie crumbling in the desert of Peru. They are famous both for the fabulous treasures of gold and silver looted from them, and for their unique maze-like plan. How did such a city arise? What is the meaning of the strange walled compounds, pyramids, the secret rooms of which the ruins consist? "Horizon" sifts the evidence from the sand and builds up the story of a savage people. Drawing on proof of battle and human sacrifice, it lays bare the secrets of the Lords of the Labyrinth.