expedition to the ruins of greyhawk is an adventure book for the 3.5 edition of the "dungeons & dragons" fantasy role-playing game. the adventure is set in the game's world of greyhawk campaign setting, specifically in and around castle greyhawk and its dungeons. as such, it is an update to the 1990 adventure module wgr1 - "greyhawk ruins". the adventure also provides updates on a number of important greyhawk personages as well as encounters in the free city of greyhawk itself.