Waterdeep: Dungeon of the Mad Mage

Waterdeep: Dungeon of the Mad Mage is a 5-edition Dungeons & Dragons adventure that takes place in the dungeon of Undermountain, located under Waterdeep. it will follow the Waterdeep: Dragon Heist adventure through levels 6‒20.

Blurb
"The Greatest Dungeon of Them All

Explore the mega-dungeon of Undermountain in this adventure for the world's greatest roleplaying game.

In the city of Waterdeep rests a tavern called the Yawning Portal, named after the gaping pit in its common room. At the bottom of this crumbling shaft is a labyrinthine dungeon shunned by all but the most daring adventurers. Known as Undermountain, this dungeon is the domain of the mad wizard Halaster Blackcloak. Long has the Mad Mage dwelt in these forlorn depths, seeding his lair with monsters, traps, and mysteries—to what end is a constant source of speculation and concern.

This adventure picks up where Waterdeep: Dragon Heist leaves off, taking characters of 5 level or higher all the way to 20 level should they explore the entirety of Halaster’s home. Twenty-three levels of Undermountain are detailed herein, along with the subterranean refuge of Skullport. Treasures and secrets abound, but tread with care!"