Toby O'Dare, former government assassin, is summoned by the angel Malchiah to fifteenth-century Rome — the city of Michelangelo and Raphael, of Leo X and the Holy Inquisition — to solve a terrible crime of poisoning and to uncover the secrets of an earthbound restless spirit, a diabolical dybbuk. Toby is plunged into this rich age as a lutist sent to charm and calm this troublesome spirit.