Rumors of powerful demon lords such as Demogorgon, Orcus and Graz’zt terrorizing the denizens of the Underdark have begun to filter up to the cities of the Sword Coast. The already dangerous caverns below the surface are thrown into ultimate chaos, madness and discord.

Our heroes must stop the madness before it consumes the Underdark and spreads to destroy the surface folk of Faerûn!