From publisher blurb:
Szass Tam, the lich lord of Thay, and his Red Wizards threaten to dominate all of the Sword Coast. The Bloodgate, an elemental node of power, must be destroyed in order to stop him. This adventure is part two of the Dreams of the Red Wizards Sundering storyline, directly tied to Scourge of the Sword Coast, and loosely connected to the events in Ghosts of Dragonspear Castle.
Dead in Thay is a tribute to Tomb of Horrors, The Ruins of Undermountain, and other killer dungeons. The monsters, traps, and hazards in the adventure create a deadly challenge.