From publisher blurb:
Halidom is a high-level series of adventures that send the PCs off on a perilous journey deep into the heart of unknown country - the lands of old Wyoming. Their goal: to track down the Doomriders, a monstrous raider gang with epic nihilistic goals, who by all accounts have returned from a generations-long absence to begin anew a campaign of destruction, sparing none whom they find in their path. No mere raider war, something behind the scenes seems to be driving the vast armies of the Doomriders into a blood frenzy that could only come from their legends of a "Second Apocalypse".
Homesteads, villages, and towns have been laid waste, with every last inhabitant viciously slaughtered like livestock. What's worse, a hideous disease is spreading through the lands the Doomriders have passed through, threatening even more lives. To end this great threat to the Twisted Earth the characters are hired to travel many miles, over mountains and open plains, through the territory of new and unusual groups unheard of in more settled lands, to the footstep of the great Doomrider fortress of "Halidom". Braving the mighty citadel they must infiltrate its deep caves and assassinate whatever mysterious leader is behind the re-emergence of the hated Doomriders.
The Halidom campaign should ultimately take characters from level 10 to 18