This is the next on the series of adventures of three young archeologists called the Archeo's. Sam, Yoder and Mike are the grandsons of Dr. James Michaels, an internationally renowned archeologist. He has taken them with him since they were toddlers on what he calls his expeditions in time. The Archeo's, having finished their junior year in high school, have been spending the summer with their grandparents in their home on the edge of the great northwest wilderness. At the outset of the summer they made one of the greatest archeological finds of all time. They called it the Valley of the Dwellers. Soon after that they accompanied their grandfather in the search for Chi Chaco, the ancient city of the Anasazi. That search was fraught with danger as they were pursued and nearly captured by the Askooks, a notorious ring of ancient artifact thieves. It was from that expedition they learned of the existence of several crystal skulls that had ominous reputations. Through Sam's research they discovered there was a crystal skull said to be more powerful than any yet found that Sam thought might possibly be hidden somewhere in the Valley of the Dwellers. What they discover will change their lives forever.