On a rugged Colorado mountain ridge, Mattie Cobb and her police dog partner Robo make a grisly discovery - and become the targets of a ruthless killer. Colorado's Redstone Ridge is a place of extraordinary beauty, but this rugged mountain wilderness harbours a horrifying secret. When a charred body is discovered in a shallow grave on the ridge, officer Mattie Cobb and her K-9 partner Robo are called in to spearhead the investigation.