On the hunt for a life-giving aeon orb far below the surface world, the heroes venture into a blighted Darklands waste known as the Vault of the Black Desert. Facing off against lurking, vampire-like urdefhan and even stranger subterranean beasts, the heroes track the lost artifact to an enclave of undead dark elves in the twisted city at the vault's blackened heart, where they must confront the malevolent mummy who strives to become the desert's eternal sovereign "Lord of the Black Sands" is a Pathfinder adventure for four 15th-level characters. This adventure continues the Extinction Curse Adventure Path, a six-part, monthly campaign in which the heroes lead a traveling circus as they unravel a plot to eradicate all life from the islands of the Inner Sea. This volume also includes a gazetteer of the ominous city of Shraen, new monsters, and new rules. Each monthly full-color softcover Pathfinder Adventure Path volume contains an in-depth adventure scenario, stats for several new monsters, and support articles meant to give Game Masters additional material to expand their campaign. Pathfinder Adventure Path volumes use the Open Game License and work with both the Pathfinder RPG and the world's oldest fantasy RPG.