From the Back of the Book:
The Merchant Consortium's guild master has been murderer. The Slayer's Brotherhood, the constabulary, sanctioned private ventures, and the Lankhmart Army mobilize to find the killer, but they soon realize he is no average person. Intelligent, cunning, sly, and brutal, he may be the most diabolical murderer in Lankhmar's criminal history.
This adventure features new weapons, new proficiencies, a detailed map of a portion of the Hlal Forest, and 64 pages of unforgettable mayhem guaranteed to keep player characters on their toes.