For the life of me, I don't know how this one got published. It has the most nonsensical plot I've ever read in all my 30 years of gaming. After the PCs disrupt attempts to conquer Kentaria in Part 2 of the AP and cause anarchy in the streets, they're summoned by Archbaron Fex. There, they learn that while they were stopping the Glorious Reclamation at Kentaria, the town of Senara has fallen. But rather than aid any efforts to help retake Senara, Fex first has you swear loyalty to House Thrune, and then...ride off on a ridiculous fetch quest to gain the components needed to close a gate to Hell.
No, seriously. I have no idea why anyone thought this would make sense. In a nation full of devil-binders - where the state-sanctioned religion is the worship of Asmodeus - why would anyone loyal to the ruling house want to SHUT DOWN a gate to Hell in the middle of an insurrection? Wouldn't it make more sense to gain control of said gate so it could pour devils onto the ranks of the holy knights threatening to overthrow Cheliax? The logic breaks down even more when the PCs meet some Hellknights of the Order of the Pike in a place called Citadel Ordeial. These guys are monster hunters and are at least dimly aware that an open gate to Hell causes random devils/monsters to romp about in the woods around the Citadel. Uh, okay monster hunters, when did you plan to get on that?
Sadcasual did a great job explaining how stupid the encounter with the "tired paladin" is. I can't imagine any party of evil-aligned characters would allow that guy to live. That's forgetting that the whole thing makes zero sense in the first place.
I think the author tried to salvage things in the end by opening the possibility that the PCs would find a way to take control of the Inferno Gate themselves. I think that's highly, highly unlikely. The encounter with Fex at the Gate is sure to spark a slog of combat that will only end with both the heresy devil and the wizard dead.
All in all, a very disappointing part of an AP that has a very weak start to begin with.