It is 1626. On a stormy night in the Scottish town of Banff, the apothecary's assistant collapses in the street. The next morning he is found dead in the house of Alexander Seaton, a fallen minister, and reluctant, embittered teacher. Murder is suspected and when one of Alexander's few friends in the town is arrested, Alexander sets out to prove his innocence. Forced to confront his own demons, Alexander also has to contend with inflamed bigotry, a witch-hunt, and accusations of treacherous Catholic plotting.