On a dark night in the 1590s Adam glimpses the Devil. Terrified, he is even more alarmed when he discovers that little Gilly, the timid kitchenmaid, is the thirteenth member of a witches coven, and like all the other witches, risks a fiery death at the stake for her devil worship. With the help of the Alchemist, Master Grahame, Adam is determined to foil the coven's plot to kill Scotland's king. But what is the Alchemist's dreadful secret, and how...