Skinwalker! Summer of Stolen Souls

Old Bob, an aging Ute Medicine Man, is destined to fulfill an ancient legend. He and his closest friend, Jerry Cloud, keep this knowledge secret for over forty years.
This secret has its toll on them, and in spite of their life-long bond, distrust begins to eat away their friendship.
The old shaman's prophecy foretells the coming of a vile, ancient shapeshifter by the name of Nyatt. The evil entity will enlist skin walkers to steal human souls to help him escape from a portal hidden in the Uinta Mountains. In the summer of 2000, the killings begin and a confrontation with Nyatt is imminent.
The medicine man convinces his incorrigible grandson, Manny, to prepare for an Indian warrior's battle against Nyatt and his army of skin walkers. After Old Bob calls for the gathering of four mysterious crystals, Manny and three of his non-Native American friends, unwittingly, submit to their part in fulfilling the legend. They discover the veil between reality and the supernatural is the width of a fly's hair. Untimely deaths, love gained and lost, insanity, human conflict, and inexplicable horrors besiege the band of motley, modern warriors.