From publisher blurb: For a level 12 party! Agents of the Underdark are attempting to complete a dark ritual in the icy depths of Gloomthrone Citadel, a ritual that would surely spell disaster for the kingdom if completed! Led by the priestess of Lolth, Z'ress Baenre, a coterie of drow have overtaken the abandoned tower and fortified it with their minions. It's a race against time for the PCs to make their way through Gloomthrone's defenses, and put an end to Z'ress and the foul magic she is using.