A.D. 1311. Mondino is a university anatomist - a man of science in a land governed by the Catholic Inquisition. But the corpse brought to Mondino's laboratory one stormy night defies natural law: the victim is a Templar knight, and his heart has been transformed into a block of iron. Is it alchemy? Or the diabolical work of an ingenious killer? Mondino must outwit both ruthless Inquisitors and vengeful Templars if he's to stop a murderer who threatens to shake the very foundations of Christendom.