Narrated by actor Memo Sauceda, MYSTERY OF THE MOUNTAIN: HIDDEN IN PLAIN VIEW chronicles a most intriguing and remarkable story, and explores the question: what if one of the world's largest pyramids is waiting to be unearthed in Mexico? For centuries, a rugged and venerated hilltop in Mexico has borne witness to the rise and fall of pre-Columbian societies, and to the creation and destruction of temples and pyramids. It is also the focal point of a most unlikely mystery, and a possible sacred... [see more] structure lost to history. The program investigates one of the few clues that remains today: a 430-year-old map that was carefully redrawn and passed down from generation to generation. The map depicts what would be one of the largest step pyramid structures in known history. Is it a coincidence that the hill that exists today, revered by the local people, is aligned perfectly with the zenith sunrise, the constellation Orion, and the nearby Cholula, the largest existing pyramid (by volume) in the world? Or, could it be possible that an ancient people calculated, measured and constructed a sacred burial chamber that still lies beneath the surface of this mysterious mountain? A valley in Central Mexico offers the setting for a fascinating look at this ancient mystery.