One morning in 1995, Jonah Ransom, clothier, is going about his everyday business when he meets a beautiful demon in his storecupboard. At around the same time, the King of England with his entire court, vanishes abruptly before the astonished eyes of his public as he prepares to attend Mass. Even in an England where the Reformation failed, and magic has become a commonplace tool of the all-powerful Catholic Church, such events could be described as unusual.
Before long, it is apparent that something very different is abroad - magic ceases to work in its accustomed way, instability and political unrest threaten to disrupt a society used to order and rigid social obedience. Eventually the Pope is sufficiently perturbed to send one of his beloved (by him) and dreaded (by the public in general) Sicarii to investigate the disturbance. Arriving late on the scene, Adam (he has no other name), Sicarii extraordinaire, sometime spy, sometime security officer, sometime assassin, discovers a mystifying, malicious power at work, a power that can twist not only souls, but his entire world inside out.