Murder in Thay

From the back of the book: With the rise of Tiamat threatening to destroy the world, the undead masters of Thay have approached the Council of Waterdeep to discuss the possibility of an alliance. But the Dragon Queen has agents everywhere, even in a remote keep on the Thayan frontier. A vampire noblewoman has been killed, and the characters are the prime suspects. To clear their names, they must find the real killer, and learn how even the undead may die… For characters of levels 13-14