Byzantium, 1096. When a mysterious assassin looses his arrow at the emperor, he has more than a man in his sights; the keystone of a crumbling empire, he is the solitary figure holding its enemies in check. If he falls, then the mightiest power in Christendom will be torn apart. Aware of the stakes, the emperor hires Demetrios Askiates, the unveiler of mysteries, to catch the would-be-killer. But Demetrios is entering an unknown world, a babbling cauldron of princes, slaves, mercenaries, pimps and eunuchs. From the depths of the slums to the golden towers of the palace, and from the sands of the hippodrome to the soaring domes of Ayia Sophia, he must edge his way through a glittering maze of treachery and deceit before time runs out. Nor are all the enemies within the city walls. With the Turks rampant across Asia, the emperor has sent to the west for mercenaries to reinforce his position. He gets more than he bargained for, however, when a great army, tens of thousands strong, appears before the gates. The first crusaders have arrived, intent on making their fortunes in war, and they have no allegiance to an empire they eye with jealousy and suspicion. As the armies of east and west confront each other, and the assassin creeps ever closer to his prey, Demetrios must untangle the golden web of intrigue which surrounds the emperor before the city - and the empire - are drowned in blood.