Detective Inspector Tony McLean is on the case when the search for a missing journalist uncovers the scene of a carefully staged murder. In a sealed chamber, deep in the heart of Gilmerton Cove, a mysterious network of caves and passages sprawling beneath Edinburgh, the body is discovered in a seemingly macabre ritual of purification. But McLean knew the dead man and can't shake off the suspicion that there is far more to this case than meets the eye. Teamed with the most unlikely and unwelcome of allies, McLean must track down a killer --- driven by the darkest compulsions and who will answer only to a higher power --- until it's his own blood on the altar.

The murder/suicide of a prominent Scottish politician and his family brings Edinburgh-based Detective Inspector Tony McLean out to the countryside to investigate. The powers that be want a quick report and then to have the whole thing buried, but McLean believes there's more to the case than meets the eye. The more lies he uncovers, the more McLean comes to realize there is a connection between the influential politician and another case he's working --- the body of a man, covered from head to toe in fresh tattoos, found in a river to the south of Edinburgh. But investigating the link between the two could have detrimental implications for his career, not to mention his life.