When Holda Weisel's Cambridge professor sends her to Germany to investigate a recently discovered medieval diary written by a 14th century necromancer, she already suspects he knows more than he is letting on. The mysterious leather-bound volume exerts a diabolical influence on those who come into contact with it, including Rupert Keller, the attractive German archivist who now has care of it. Holda learns about a grisly murder two centuries earlier...