Pool of Radiance – Attack on Myth Drannor, Forgotten Realms adventure for D&D 3rd/3.5th ed, by Sean K. Reynolds.
“Where elves once built the shining city of Myth Drannor, demons and devils now prowl in search of prey. Ancient evil slumbers beneath mossy stones, waiting for those foolish enough to venture within its grasp. Bold swordsmen, stealthy rogues, and skillful wizards have all met their end within the walls of Myth Drannor. But the lure of the city’s magical treasures still draws heroes and villains alike to tempt death – or worse.
Drawn by the dream of limitless magical power, the Cult of the Dragon has carved out a secret stronghold in the heart of the ruins. Using the power of a corrupted pool of radiance, the Cultists stand poised to attain their goal of subjugating all of Faerûn.
Unless a group of brave heroes can stop them first….
This adventure can be played as a stand-alone or as a tie-in with Pool of Radiance: Ruins of Myth Drannor computer game.”
For 6th level characters.