Undermountain: Maddgoth's Castle

From the back cover: This Dungeon Crawl adventure returns once again to the hallowed halls of Undermountain and into an adventure like those AD&D game archetypes of years past. This is a stand-alone module and does not require extra support materials. It can be placed easily into a campaign on any AD&D world, but best fits a Forgotten Realms campaign set in Undermountain or Waterdeep.