Paris, 1534. A courier for the Inquisition is murdered by a Lutheran sect for the packet of letters he is carrying, in this novel by the author of The Anatomy of Deception. Young Amaury de Faverges—an illegitimate son of a duke, and a student of astronomy—is promised a decree of legitimacy if he can thwart this plot against Catholicism and François I. Suspicion has fallen on the king's sister, Marguerite of Navarre, and Amaury travels in disguise to her court. There he meets the infamous Copernicus, and—confronted with the idea that the planets revolve around the sun—Amaury begins to question his own faith, and if he should turn against his masters.