It is 1899, and Doctor Varanus is in Prague with her mentor Iosef, both still recovering from the scars of the Shashavani civil war. Iosef has found a reprieve from grief in the study of the so-called "Black Goat" cults, aided by a charming Prussian nobleman and a mysterious bookseller. Under other circumstances, Varanus might regard Iosef's fascination with occult philosophies as troublingly superstitious, but she has greater concerns. Her wayward son Friedrich has taken up residence in Prague as well, and in the company of artists, revolutionaries, and other such rabble-rousers.

As Varanus endeavors to carry on her research and drag Friedrich back into respectable society, she discovers something sinister may be at work in the Kingdom of Bohemia. Could there be more to Iosef's occult studies than he or his new friends realize?

Truth or fantasy, a shadow looms over Prague, threatening to drag Varanus and all she holds dear into the darkness of an unending night . . .