From the back of the book...
Visit the Abyss.
Meet Demon Lords.
In the heart of the Demonweb, Lolth surveyed the Grand Council Chamber and the demon lords assembled by her invitation. Throaty growls indicated a dispute among Yeenoghu's pack. Obox-ob's insect swarms chittered while Demogorgon ranted from the central podium. The other emissaries seemed restless. Across the hall, Graz'zt met Lolth's gaze and smiled. The demon queen shivered with a tingle of foreboding
This DUNGEONS & DRAGONS adventure takes characters from the planar city of Sigil to the darkest corners of the Outer Planes, gathering resources to battle the forces of Lolth, Demon Queen of Spiders. The player characters must navigate a carefully spun web of treachery and deceit to reach the violent heart of Lolth's domain and put an end to her sinister dreams of conquest.
This campaign adventure is designed for characters of levels 9-12 and features an easy-to-use combat encounter format and player handouts. This book also presents new prestige classes and magic items for player characters.