For Duty & Deity, Forgotten Realms adventure for AD&D 2nd/2.5th ed, by Dale Donovan.
“For over a decade, mystery has surrounded the fate of the lost goddess of trade and wealth, Waukeen. The Golden Lady disappeared during the Time of Trouble and has not been heard from since. Now, in Marpenoth in the Year of the Tankard (1370 DR), a young prophet suffers from disturbing, divine visions that reveal a beautiful, golden-tressed woman imprisoned on a far plane of existence by some great evil.
The leader of Waukeen’s church believes that these visions mean Waukeen is alive but trapped in the deadly and dangerous Abyss. A party of adventurers is dedicated to peeling back the mystery of the Golden Lady’s fate. Their route takes them to the plane-spanning Infinite Staircase and beyond, to the Abyss, the home of the demonic tanar’ri. The heroes must brave the dangers of the Abyss and rescue the lost goddess from the clutches of one of the most brilliant and dangerous of all Abyssal lords.
This stand-alone adventure was developed in concert with the PLANESCAPE adventure anthology Tales from the Infinite Staircase. They can be played separately. However, guidelines within both allow a Dungeon Master to use either product as a subplot for the other, creating new opportunities for player characters and extending the opportunity for adventure.”
For characters of levels 10-12.