Explore the Undermountain Mega-Dungeon in this adventure for the world's largest role-playing game.
In the town of Waterdeep lies a tavern called the Yawning Portal, named after the gaping pit in its common room. At the bottom of this ruined hole is a labyrinthine dungeon shunned by all but the most daring adventurers. Known as the Undermountain, this dungeon is the domain of the Mad Wizard Halaster Blackcloak.
For a long time the Mad Mage lived in these desperate depths, sowing his lair of monsters, traps and mysteries - to what end is a constant source of speculation and worry.
This adventure picks up where Waterdeep: Dragon Heist goes, taking characters from the 5th level or higher up to the 20th level if they explore the entire D'Halaster house. Twenty-three sub-mountain levels are detailed here, as well as the Skullport underground refuge. Treasures and secrets abound, but walk carefully!