Planescape Cold War

"Intelligence work has one moral law—it is justified by results."

- The Spy Who Came in From the Cold, John Le Carre

This is what comes of seeing The Man from U.N.C.L.E. (2016) and Atomic Blonde in the same weekend.

Take Planescape's Sigil and re-imagine it as vaguely post-World War (it really doesn't matter which one) in technology and sensibility. It's the center of fractious sometimes warring (but mostly cold warring) planes, but now it's more like Cold War Berlin or Allied-occupied Vienna.

Keep all the Planescape factions and conflict and you've got a perfect locale for metacosmic Cold War paranoia and spy shennanigans. You could play it up swinging 60s spy-fi or something darker.

There's always room for William S. Burroughs in something like this, and VanderMeer's Finch and Grant Morrison's The Filth might also be instructive. Mostly you could stick to the usual spy fiction suspects.