At the basic level, it’s a story about a fantastic world underneath the city. I personally find that the Underground puns are fairly significant, because they help link the wildness of the world to the reality of the city — without those allusions, goofy as they can be, the real London would have less meaning. It’s not just a fantastic world beneath the city, it’s a fantastic world that mirrors — perhaps echoes — the city.
What else, what else? Door is deposed nobility, which could be fun to play with. The Goblin Market is cool. The Marquis de Carabas is the kind of figure one might well like to use. Ditto Croup and Vandemar… heck, lots of cool characters.
By the by, we’ve added another gaming meme — the excellent Wednesday Weird — to the gamememe mailing list. Every time a meme from here, the Weird, or Game WISH gets posted, subscribers to gamememe get an email. It’s the easy way to keep up on your meme postings.
I’m gonna use Adventure! for this — set in Boston, for the sake of argument, since Boston had a decent sized subway system by the 1920s. And I do want to keep the subway system.
Names… Mr. Tremont. Scollay. The Pleasant Streets. The Court. A Friendly Union. Plenty of those.
I’ll adopt the Neverwhere world in toto. It’ll be the only supernatural aspect to the world, however — all the other pulp trappings come from superscience, one way or another. Mesmerism exists but it’s explicitly non-magical, for example.
That means the world below Boston is a complete change of pace. It might well wind up a refuge. I’d want to turn it into a place the players cared about. The surface world is dangerous and full of evil geniuses and criminals and so on; down below is a place to relax.
Until — let’s use the royalty aspect, but twist it a little — until the PCs turn out to be the lost royalty of the Pleasant Streets, and people start trying to keep them down there. First it’s subtle, later it’s overt. They’ll wind up having to chose Above or Below, and they’ll have to fight for the right to make even that choice.
(Yeah, my stuff often winds up horrific one way or another.)