Hellknight forces have forcibly taken over Citadel Altaerein, the abandoned Hellknight citadel on the edge of Breachill, a small town in Isger, while also leading a reign of terror on the innocent civilians and the leadership alike. The Eagle Knights of Andoran have called upon the Pathfinder Society for backup while they handle the citadel, requesting that they rescue the civilians and prevent any unneeded harm. While the Pathfinders are moving throughout the town, they learn of a secret way into the citadel, and though it's not without its dangers and threats, they could learn so much from the enemy...