The Thrice-Damned House of Thrune wants to seal the Inferno Gate, an uncontrolled portal to Hell, and the villainous adventurers are called to accomplish the task. To acquire the components and perform the ritual, they must first face down a hellspawn thieves' guild, the Hellknight Order of the Pike, and the knights of the Glorious Reclamation and their celestial allies. But before they can complete the ritual, the characters may be forced to examine their options—is closing the gate the best plan for the future? Will the villains obey their orders to close the gate to Hell—or might they make a deal with a devil for control of the portal? Or will they only become the latest in a long line of sacrifices to the Inferno Gate?

This adventure is the ninth part of the Shackled City Adventure Path that began with "Life's Bazaar" (Dungeon #97) Wherein a group of diverse and talented allies learns the folly of not working together against a common foe.