Edinburgh 1841. Reaching out like a hungry white worm it twisted and spiralled, tasting the air. Then, evidently attracted by the flow of warm blood, it squirmed its way under the surface of my skin.

Every autumn without fail, a strange seed appears on the chestnut tree that marks the spot where the witch Margaret McKay was murdered. Legend states that anyone who catches this nut before it hits the ground will be blessed with untold riches, but when it falls into the eager hands of botanist Joseph Ware, the seed unleashes a terrible curse. In his quest to find the cure, Joseph discovers a resistance group battling to save the last of Scotland's witches from a sinister order of surgeons who believe the key to all magic lies hidden somewhere within a witch's anatomy. The conflict quickly tears apart the bonds of family, friendship and even reality itself, as Joseph fights to save his soul and avoid the anatomists' dissecting table.