The Thirteenth Member — Mollie Hunter

On a dark night in the 1590s, Adam glimpses the Devil, near his home in East Lothian. 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, James VI. But what is the Alchemist's dreadful secret, and how can Adam save Gilly when he exposes the witches' treason?