A One-Round Living Greyhawk Duchy of Urnst Regional Adventure
From the introduction:
The fortress of Tarth Moorda has long been aligned with the Duchy, and now serves as one of the few remaining bastions of defense against Rary the Traitor. So when the Warmasters of Tarth Moorda are in need of investigators to alleviate one of their concerns, the Duke is quick to help...by sending you. A Ducal Guard adventure for APLs 4-12.