She stared back at him from the Polaroid. Her thin hands bound with white a cord, her mouth covered by a rectangle of grey duct tape. The camera's searing white flash had bounced off the sloppy mortar between the bricks of her homemade cell and caught the aching terror in her tear-stained eyes.

After serving in The Iraq War, Zack Hall returns to the small Wyoming town where he grew up alone after his older sister disappeared in 1990. Zack befriends Ernie Schrader, a resident of the nursing home where Zack works. The two start to bond until Zack sees a Polaroid of his missing sister bound and gagged with duct tape in a cigar box full of Ernie's things. After getting Ernie into the seclusion of The Bighorn Mountains, Zack threatens the old man into telling him what happened to his sister. What unfolds is the story of one man's need to satisfy a dark urge after coming home from Vietnam, prison manacles found in a muddy cave, and a group of hooded figures led by the state's most powerful family gripped in an ancient cult requiring bloody sacrifices.