The year is 1545; Geneva has defeated the Catholic forces of the Duke of Savoy and established itself as the center of the Reformation, with John Calvin as its spiritual leader. But peace is fragile, and in a city ravaged by plague, the atmosphere is one of fear and suspicion. So when new rumors of witchcraft emerge from the isolated village of Satigny, Calvin sees an opportunity and plucks a reclusive young magistrate to investigate.

Henry Aubert was orphaned by plague at the age of twelve, and since then, he has lived alone, consumed by fear and by the temptations he finds in the margins of his book collection. Now, for the first time, he is forced to confront the possibility of society, friendship, even love. Local healer Louise de Peney is kind and beautiful but skirts dangerously close to the fringes of his investigation. Can he escape the horrific task he has been set? And is it too late to save a soul that has too long been turned in on itself?