On a battlefield strewn with corpses, a ragged figure, dressed in wolfskin and intent on death, slips past the guards into the tent of the Emperor and draws his sword. The terrified citizens of Constantinople are plagued by mysterious sorcery. The wolves outside the city are howling. A young boy had traded the lives of his family for power. And a Christian scholar, fleeing with his pregnant wife from her enraged father, must track down the magic threatening his world. All paths lead to the squalid and filthy prison deep below the city, where a man who believes he is a wolf lies chained, and the spirits of the dead are waking. The Norsemen camped outside the city have their own legends, of the wolf who will kill the gods, but no true Christian could believe such a thing. And yet it is clear to Loys that Ragnarok is coming. Will he be prepared to sacrifice his life, his position, his wife and his unborn child for a god he doesn't believe in? And deep in the earth, the wolfman howls.