Madison Evans inherits the antique turquoise locket and immediately begins having dreams of fleeing from warriors in a desert.  She travels to New Mexico and learns the piece of turquoise dates back to the Chacoan Anasazi.  When her motel room is ransacked, and she's attacked, parks ranger Lonan Stone concludes Madison's piece of turquoise is more than it seems.  It's part of the revered Fallen Skystone, ann egg size piece of turquoise on display at the Albuquerque Museium of Natural History.  The ancient stone, with mystical powers is missing two slivers, named the twins.  One is in Madison's necklace, the whereabouts of the other is unknown.  Through her dreams,she learns she's the guardian of the necklace and must protect it against those who would use it for evil.  Thrown together, Madison and Lonan, an ancestor of the Chacoan people, learn they're part of a 1000 year old prophecy which must be fulfilled to save the Anasazi heritage in Chaco Canyon, a place of religious importance to all Native Americans in the Four Corners area.  Thrust back in time, Madison and Lonan confront a witch, solve a murder, and help destroy a 1000 year old evil spirit bent on revenge against the Chacoan people.  They discover the stone's secrets and learn they must never let the two missing pieces fall into the hands of someone bent on evil.  When the twins are reunited with the mother stone, the three have the power to destroy.