It’s called Contagion of Law, a new PDF for Exalted in the Storytelling Adventure System. I can suggest it to you if you’re the Storyteller / Dungeon Master in your party. If not, this is not the book for you.
Gethamane, a city buried under stone and ice, has been the target of evil entities for centuries. Ancient beings lie entombed in the deepest recesses of its tunnels, marauding predators claim the flesh of anyone foolish enough to seek the treasures below, the gods spread their centuries-fostered insanity, and now even Deathlords seek to control this refuge of civilization in the vastness of the North. The people of Gethamane keep to themselves, fearing outsiders only slightly less than they fear the monsters that live in the ancient hollows beneath them.
Yet, this frozen region holds not only dangerous monsters, but also great treasure. Some secrets will lie buried for ages, but one treasure, a crown capable of ruling nations, is about to be uncovered. Will it fall into the hands of Solar Exalts or become the property of the many evils that plague the city under the mountain?