The first victim is a horse: its headless body hangs suspended from the edge of a frozen cliff.

On the same day as the gruesome discovery, a young psychiatrist starts her first job at a secure asylum for the criminally insane, just a few miles away.

Commandant Servaz, a Toulouse city cop, can't believe he has been called out over the death of an animal. But there is something disturbing about this crime that he cannot ignore.

Then DNA from one of the most notorious inmates of the asylum is found on the corpse... and a few days later the first murder takes place.

In this snowbound valley, deep in the Pyrenees, a dark story of madness and revenge is unfolding. It will take all of Servaz's skill to solve it.