From the back cover:
The battle between the mighty undead army of the Witch-King of Vaasa and the forces of Bloodstone has come to a standstill. As long as the source of the Witch-King's power is at work, his evil forces will never be defeated!
As the rulers of Bloodstone Pass, it is up to you to find and destroy the source of Vaasa's power. All you have to do is journey to the Abyss, confront the mightiest emon of all, steal the Wand of Orcus, and take it to the Seven Heavens to be destroyed.
The Throne of Bloodstone is the fourth and final installment in a series of modules specially designed for high-level characters. While it is not necessary to have played any of the three previous modules, The Throne of Bloodstone is the climax of an epic struggle for a kingdom against the forces of darkest evil. Recommended for characters of levels 18-100, The Throne of Bloodstone is the highest-level adventure ever published by TSR!