Agnes Sampson is a respected and praised folk healer in sixteenth-century Scotland. Caught in a ferocious feud, the Wise Wife of Keith ends up as the most wanted witch; accused of plotting against the life of James VI of Scotland at the Devil's behest. For this despicable crime against God and his anointed, she is tried and burned at the stake; her tormented spirit cursed to wander the Palace of Holyroodhouse perpetually.
Four hundred and thirty years later, a mysterious necromancer empowers her ghost in return for the means to exact a righteous revenge. Before long, the wicked duo wreaks havoc in the City of Edinburgh. Their final objective: the demise of the newly crowned Charles III. He shall be punished for the despicable deceit of his forefather.
Yet, their impeccable plan is unexpectedly tampered by five international students, led by François, a timid scholar, and Callum, a gifted witch.
Follows a merciless confrontation which will ultimately decide the fate of Agnes' soul.