From the introduction:
The castle atop Hellknight Hill, Citadel Altaerein, has stood abandoned for years in eastern Isger—a legacy left behind by the Hellknight Order of the Nail that’s largely ignored these days by the populace of the nearby town of Breachill. But when strange signal fires begin to burn atop the citadel’s battlements, a local goblin and friend of Breachill’s citizens begins to worry, for her tribe, the Bumblebrashers, live within the castle. She fears the fires are distress signals, and hopes to attend Breachill’s monthly Call for Heroes to ask for help from a band of local adventurers. As fate would have it, this call for aid comes to your group of heroes, and as a mysterious doom draws near, who could have predicted that such an act of local heroism would eventually lead to the unmasking of one of the most insidious and dangerous conspiracies of the Age of Lost Omens?