From the front page of the PDF:
A One-Round D&D LIVING GREYHAWK®
Iuz’s Border States Metaregional Adventure
Recently, two adventurers with critical information regarding the Old One’s plans have been slain while operating in the Old One’s lands. While both of the bodies were recovered, attempts to bring them back to life, or even talk with their spirits using magic, have failed. What information did they carry, and how can that information be retrieved? In order to get answers, you’ll have to travel again into enemy territory, and come face-to-face with the Lord of the Tower of Blasted Bones. An Iuz’s Border States metaregional adventure, recommended for characters levels 9-17 (APLs 10-16). This is the final adventure in the Purification Cycle.