D4: Castle Greyhelm!
Well Dave FoO, Odin really could take it or leave it. Just as long as you're doing your thing, he doesn't really care who owns your soul. Just as long as it's not Loki or the Midgar Serpent or that dwarf who stole the Ring of the Nibelung or someone. Zelba's a'ight.
Nope, Vrill's gone to Greyhelm himself, with a batch of adventurers fresh outta the Tower of Illusion. Word is that he's found a magical means of getting inside the Castle itself, which was magically sealed just after the initial invasion, but fortunately just after the royal family escaped.
Off to Greyhelm. This commences module D4: Castle Greyhelm! The exciting (putative) conclusion not only of the very popular D set of modules, but of the entire Grito cycle! I hope you've all bought enough healing potions, 50' ropes and such, because you're going to be in it for the long haul, people. Also, divvy up Cinder's gear as you see fit. You guys are gonna want magic weapons for this one. Anyone who wants to retroactively buy stuff, you gotta do it soon, but the window's still open.
It takes several days, but you finally roll on up to the Greyhelm environs. At the top of a hill overlooking Greyhelm, Castle Greyhelm, and Greyhelm Lake, you can see that Castle Greyhelm still stands! Across the way, within the limits of the ruined city, you see a strange metal tower that the Knights of Armek have been building. Guys, you get the sense that the place is crawling with the KoA... unless you really want to fight tons of them, you better have a game plan. Constitutive 'plan B': FIGHT, is probably a death wish here.
Whatcha goin' do?