I'm about 2/3 of the way through Charles Stross' latest Laundry Files novel, The Apocalypse Codex, and can't shake some ideas for crossover fan fiction. (Not that I would ever urge anyone to violate an author's copyrights. This is just some First Amendment-protected theorizing.)
For the benefit of those who have not been following the Laundry Files series, here's what Wikipedia says about it:
A series of science fiction spy thrillers about Bob Howard, a one-time I.T. consultant, now field agent working for British government agency 'the Laundry', which deals with occult threats. Influenced by Lovecraft's visions of the future, and set in a world where a computer and the right mathematical equations is just as useful a toolset for calling up horrors from other dimensions as a spellbook and a pentagram on the floor.
As I understood the eraly novels in the series, you had to have a computer to do magic. This is so because, as narrator and principal POV character Bob Howard observes, in the Laundry Files multiverse "Magic is a branch of applied mathematics: solve theorems, invoke actions, actions occur." (ibooks page 349)
In recent volumes, however, we learned ritual magic -- i.e., working magic, raw, by force of will -- works, albeit not reliably and at the risk of blowing the practitioner's "cerebral cortext." We've also learned that can do the necessary computations in their heads, albeit "risking death by Krantzberg syndrome and worse." Indeed, we're told that one leading theory is that "the human brain is a computational organ. We can carry out computational tasks, yes? We’re not very good at it, and at an individual neurological level there’s no mechanism that might invoke the core Turing theorems ...."
But if there were such a mechanism? That's where the crossovers come into play.
The Laundry Files x Dune
Sometime in the near future, the singularity occurs. Skynet goes active. The Machine War breaks out. Colossus and Guardian link nets. Humanity prevails, but the Butlerian Jihad knocks out all computational devices more sophisticated that a four function hand calculator.
The Jihad delays CASE NIGHTMARE GREEN long enough for the Mentat discipline to develop. But the apocalypse is still out there, so Leto II implements his Golden Path to produce a cadre of intuitive prescient Mentats capable of conducting computational demonology and the rest of the math/magic tools without risking death by Krantzberg Syndrome. Leto deems the personal and social costs of the Path essential because he knows that at the heart of CASE NIGHTMARE GREEN are Marty and Daniel, who are Lovecraftian horrors beyond the ability of anyone other than the God Emperor to comprehend.
How to work the Bene Gesserit, the Kwisatz Haderach, et al. into the story is an exercise I'll leave for the reader.
The Laundry Files x Chuck
First, we have to eliminate the entire 5th season of Chuck, which would make me very happy. I hated the fifth season and especially the series ending as much as I loved the first four seasons.
In the crossover, Black Chamber tech agent Stephen Bartkowski and Laundry tech Hartley Winterbottom are developing the Intersect as a way for agents to conduct the necessary computations to work magic in their heads without risking death by Krantzberg Syndrome. Harvey goes undercover with the KGB to take advantage of the Thirteenth Directorate's research. An accident with an early version of the Intesect turns Harvey into Alexei Volkoff. Once Alexei recovers his memory and goes back to being Hartley, he and Chuck develop the Intersect 3.0, which finally makes it possible to conduct computational demonology in one's head. Through a mishap, Morgan is the first person to download the new Intersect, which leads to various humorous subplots.
Along the way, they discover that Decker is heading up the Black Chamber, which is seeking to prevent the final development of the Intersect because they worship the Elder Gods. Casey and Gertrude take out Decker, clearing the way for his team to go operational with the new Intersect.
Carmichael Industries, Volkhoff Industries, and the Laundry unite forces to face CASE NIGHTMARE GREEN.