After the death of her soulmate Kay by her very own sword, Billi SanGreal has thrown herself into the brutal regime of Templar duties with utter abandon. There is no room for feelings any more - her life is now about hunting down the Unholy.

But when Billi and another Knight Templar are caught at the heart of a savage werewolf attack, only Billi survives - except for a young girl at the scene who Billi unthinkingly drags away with her as they escape. But Vasalisa is no ordinary girl. She is an avatar with an uncontrollable power - and it's not only the werewolves who want her.

Billi has to flee to the frosty climes of Russia, with a human timebomb who, it seems, could destroy the world . . .