Delve deeper than you ever thought possible in this adventure for the world’s greatest roleplaying game. Hundreds of years ago; long before Waterdeep had been built; Halaster Blackcloak carved a vast dungeon beneath Mount Waterdeep and stocked it with all manner of creatures from across the planes. Over time Halaster has gone quite insane and the dungeon he carved; now dubbed Undermountain; is a labyrinthine death trap for those bold enough to venture within. Precious few have returned from Halaster’s home; and frequently they’re not who they were when they started out. One thing is certain however. Wealth unimaginable exists within the halls of Undermountain.