Dawn creeps over the horizon, illuminating the body lying on the marshy ground. He looks peaceful, young, healthy. But there is no bloom of life in his cheeks, his eyes are cold and dead…

When Head of the Ritualistic Behavioural Crime Unit, Dr Harrison Lane, is called to desolate Wicken Fen to assist with a murder investigation, he can’t believe what he sees. Curved iron horseshoes hold down the body of a young, athletic man, and birch leaves rest delicately upon his torso, but it’s what lies above the leaves that interests Harrison…

A small bone hangs around the young man’s neck and Harrison immediately recognises it as a magical talisman, said to bring the wearer great powers. But it’s from an ancient sect which some believe has links to the devil.

The victim is soon identified as local jockey Paul Lester. Searching his home, Harrison discovers a thick white envelope containing horsehair and cryptic directions to a meeting place. With a sickening feeling, he suddenly understands why Paul was targeted; he was a member of another secret society: The Horsemen. Could that mean that other members are in danger?

But Harrison can’t get the detective in charge of the case to take his worries seriously. Then another victim is found dead, pinned down by horseshoes, and his worst fears are confirmed. Harrison knows the fastest way to stop this killer is to infiltrate the society, but can he discover their secrets and work out how the killer is tracking them before it’s too late?