I've been playing World of Horror, which officially releases next month (and which you should grab before it's price goes up with that official release), and it's made me think about an old campaign frame I once discussed with one of the Nightwick Regulars but still haven't been able to pull off. Here I wish to revise that campaign frame into something more concrete and see how it sounds to my gentle readers.
First, we need the equivalent of the Spiral from Uzumaki, the overall theme and phenomenon that will drive the strangeness of the campaign. Here is the first place I wish to borrow from World of Horror: we're going to have the imminent return of a Great Old One. For my example here I'm going to pick Cthulhu but I think you'll see any of them can work. An important thing here is we don't want one organization that is trying to summon Cthulhu, but rather he is coming and his influence is spreading throughout the world. If you're playing Delta Green, we can do that literally, but if we're doing more traditional Call of Cthulhu or Liminal Horror, or especially if you're doing Liminal High School, we're going to be focusing on how this effects one town.*
Why a Great Old One? They're thematically broad, like the core phenomenon of Uzumaki. Cthulhu is most utilized in scenarios in the form of Innsmouth/Deep Ones stuff, but remember that the story the Call of Cthulhu is about his effects on dreamers and artists. The madness of dreams could certainly show up in a number of scenarios, as could ancient artwork that seems to resemble the modern, or what of the "white pulpous thing" in the swamps of Lousiana or the stellar nature of his star spawn, or even his defeat of other intelligent races in Lovecraft's Mythos? Maybe a Elder Thing ruin activates an ancient weapon meant to stop Cthulhu's return based on math created by that ancient race but now it will destroy the town the PCs occupy. I dunno. Lots of stuff. If you need ideas for expanding the meaning of your respective Great Old One, check out the section on them in Trail of Cthulhu or, if you have it, the d20 version of Call of Cthulhu.
Next we come up with 1d4+2** of mysteries around the town.*** In my head players will have access to the hooks for these all at once. In my original Lerouxville campaign the analogous list of hooks came in the form of the notes of a missing friend. He had collected a number of notes on the outer layers of various mystery-onions**** and the players could kind of pick which one they wanted to investigate. Unfortunately I did not have these as thematically consistent as we want here - they were just a bunch of weird things - nor did I have the intention of ever revealing the fate of the missing friend. In hindsight I should've probably made that explicit - "you're never going to actually find out who killed Laura Palmer, that's just the frame for the other stuff" - but the first part is remedied by this campaign model. How you develop these mysteries is up to however you do it normally. I'm a fan of the method in the DG Handler's Guide, but you do you.
For the sake of our Cthulhu example, and because I have Liminal High School on the brain, maybe some high school Wicca types were all visited by him in a dream and now they're out in the swamp feeding people to those polypous things. Get a list of NPCs, leads, maybe a handout for one of their dream journals, and you have a scenario.
As I hinted at above, our example for this is going to be a dream-driven deep one with a fire axe that'll attack the PCs during one of their investigations. What's his deal? Unfortunately for the PCs, that's likely to be a dead end; however, he sets up the broader theme of the Great Old One thematically and introduces an element of horrific synchronicity into our game.
So why do this? What do we get out of it? Well from our example one thing we get out of it is potentially a higher density of weird moments instead of mundane detective work. I know a player who has disliked most of the CoC/DG games run by the Nightwick Regulars because of the lack of relative action. This perhaps does something to remedy that. Hopefully. It also sets up foreshadowing for the final bad thing in our Uzumaki spiral. And if you want to be real pretentious about it, and this is hack work, remember, it adds to the horror of the unknowable or some shit. Spooky!
** Not necessarily literally rolling dice but I wanted to be more concrete than "a handful."
*** Or world. Whatever.
**** To slightly borrow a metaphor from some asshole.
***** Get it? Because of the ocean?