From the back of the book:
Uncover The Ruins Of The Flying City
Legends speak of an ancient culture that drifted through the clouds atop immense floating cities. These same tales speak of a horrible catastrophe that brought them low, but no one has discovered the true cause. Now a mystical compass has been discovered that seems to point to an unexplored valley, one that might just hold the secrets of this lost empire, but will the same catastrophe strike again?
Crucible of Chaos is a journey-based adventure for 8th-level characters compatible with the world’s most popular fantasy roleplaying game. This adventure includes details on the valley containing the crashed sky-city, including the natives who live there, as well as information on those who brought about the city’s downfall.
This adventure is set in the unexplored reaches of the Mwangi Expanse, one of the regions in the PATHFINDER CHRONICLES campaign setting, but it can be easily adapted for use in any setting. For more information on this area, check out the Pathfinder Chronicles Gazetteer.