Disguised as evil dark elves, the heroes penetrate a hidden city in the subterranean Darklands in an effort to discover the drow plan for the coming apocalypse. The possibility of a traitor among the goodly elves of the surface world and the discovery of the heroes' ruse leads to a race through treacherous caverns in a desperate effort to warn allies of impending doom. This installment of Pathfinder also features a gazetteer of a complete drow city, an exploration of deformed monsters created by the dark elves, and a bonus adventure set in a remote corner of the Darklands.