A One-Round Living Greyhawk Geoff Regional Adventure
From the introduction:
The Storm King's Citadel of Thunderhead looms over the land in the far northwest of Geoff where the Crystalmists and the Barrier Peaks meet. Bigger and greater than the mountains about it, Thunderhead is the heart of the Jotunreike and the source of the Sakhut's power. The Storm King never leaves his great citadel. If the threat to Geoff is to be ended, then he must be faced there at his seat of power.
A Grand Duchy of Geoff regional adventure for APLs 12-18, and the conclusion of the Against the Giants; the Liberation of Geoff Campaign.