Pathfinder Adventure Path Ironfang Invasion Part 4 Of 6

"The Ironfang Legion's secret weapon has been revealed! An ancient dwarven artifact known as the Stone Road allows the hobgoblins to move their forces hundreds of miles at a time, completely unseen. Whatever secrets-and vulnerabilities - the Stone Road may have lie sealed within the dwarven Sky Citadel of Kraggodan. To enter the besieged fortress-city, the heroes must brave the dangers of the Darklands, including morlock fanatics and their slithering god, and duergar slavers, only to find what they need in long-abandoned corners of the ancient city now dominated by horrors from deep below!"