Having rescued what remains of the Chernasardo Rangers, the heroes have their first chance to take the offensive against the Ironfang Legion when rumors emerge of the monstrous invaders massing to the north to siege the refinery town of Longshadow. If the Legion succeeds, their inhuman empire tightens its grip across western Nirmathas, and the mines and refineries would grant them all the raw materials their engine of war requires. But the Legion's heavy focus on Longshadow leaves their flanks vulnerable to a campaign of sabotage and harassment! Can the PCs end the hobgoblin siege, and in the process discover the secret behind the Ironfang Legion's lightning-quick raids and unseen troop movements?