Rescuing local farmers from a bunch of evil cultists who have been terrifying the neighbourhood should be relatively straightforward for a high-level party... until they find they have to travel to other dimensions and battle a demon prince on his own turf before he completely wrecks their world! Small stakes, hun?
There's a note that this work references the Demon Hunter's Handbook published by Goodman Games, but that you don't need to have a copy to play. Anything you need has been reprinted here. Still, if you like battling demons, you may find it worth getting hold of it. There's a synopsis of the adventure, notes on adapting the plot to fit in with your own campaign, encounter tables, scaling information, and a whole lot of backstory to help you get set up. Recommendations are made about dealing with planar travel and dimensional effects, and there's a note that one or two bits are a bit graphic and if your players are young you might feel the need to skim over them a bit. There are a few hooks to help you get the party involved too, and ideas about how to feed them information. This last is good, because there is a lot in tbe backstory and it would be a shame if the rest of the group never found out its depths and complexity.
The Cult of the Broken Word hang out in a dark abbey, a former temple of light that they took over and corrupted ages ago, and the adventure proper begins with the party standing at the main gates of the abbey grounds. The first part deals with their passage to the front door... not as easy a task as one might expect. Notes are provided on how to deal with parties inconsiderate enough to suggest flying or teleporting to the front door. Once they reach the abbey itself, the next task is to actually get in, which is not as easy as it might be. Various routes are suggested, each with their own problems.
Once in, things don't really improve. It's a suitably perverted mockery of a monastery, with plenty of perils in the shape of traps and monsters to contend with. There is a lot to explore in even the 'normal' parts... and then it begins to get very weird indeed. There are dimensional echoes, the result of a failed attempt by the cultists to transport their home to the Abyss, then there's a rapidly-arriving chuck of the Abyss - the demon prince's palace that he's ripped out of its home dimension and is attempting to bring to the Prime Material as part of his dastardly plot. There are a couple of massive magical/technological devices that he is using to power these plans, with the party will have to figure out, at least enough to know that they ought to destroy them. These make for a suitably epic backdrop to the final battle with the demon prince himself, a finale worthy of the name. Of course, the party then have to get themselves home again...
Well-resourced with maps, handouts, good descriptions, all the game mechanics you need to run each encounter and more, there are several ideas for further adventure. There are notes on the surrounding area and on new monsters including several types of demon, and new magic items - all of which can be used as appropriate in your own games. This is an epic adventure of world-shaking proportions, quite cinematic in scale.