Expedition to the Ruins of Greyhawk, hardback Greyhawk campaign adventure for D&D 3rd/3.5th ed, by Jason Bulmahn, James Jacobs and Erik Mona.
“Mordenkainen needs you. The good people of Greyhawk need you. What are you waiting for?
Twenty-seven years ago, a band of adventurers led by the great wizard Mordenkainen entered the dungeons below Castle Greyhawk and released the evil demigod Iuz, intending to slay him. Betrayal led to failure, Iuz escaped, and many lives were lost. today, evil has returned to Castle Greyhawk, and Mordenkainen must place his trust in the hands of a new generation of heroes. Those who fail will be lost, and those who triumph will be legends.
Castle Greyhawk has become a grand fixture of the Cairn Hills, tempting the likes of Mordenkainen, Bigby and Tenser with its dark mysteries. Today it lies in ruin, ravaged by years and countless assaults. However, many of its greatest treasures and secrets remain hidden in the sprawling dungeons beneath, where terrible monsters and fiendish traps defy new generations of heroes in search of fame and glory.
This campaign adventure revisits the legendary ruins of Castle Greyhawk and its dungeons, incorporating many new twists and surprises. It is designed for characters of levels 8-13 and features an easy-to-use combat encounter format. This book also presents several new monsters and magic items.”