Evidence recovered from the devastated island known as the Devil's Elbow indicates that vile dark elves have infiltrated the ruined elven city of Celwynvian. The heroes join forces with the valorous elves of Crying Leaf in an attempt to reclaim the city from darkness. In so doing, they uncover a monstrous plot to destroy the surface world and darken the light of the sun in a world-apocalypse that leaves the dark elves victorious upon a broken world. This installment of Pathfinder also features a gazetteer of Celwynvian, a detailed exploration of the dark elves of Golarion, a bonus adventure set in the mysterious woodlands surrounding the elven city, and several new monsters native to the region.