Looking for ideas for a written fiction game

If there is a more appropriate locations for this question, please let me know.

The game (a la Zork) has multiple rooms and puzzles. The conceit is that it is an abandoned cold-war house (likely in England) that has on the surface living quarters and so forth, but you find an elevator and that takes you to subterranean rooms and caves and there's all kinds of external stuff (helipads, etc.) and the current drive is that we have secured a visitor (alien) and these were the steps and constructs around it. The visitor need not be a part- it's just a current instantiation.

But imagine a cold-war building around something very hush-hush and, perhaps, futuristic. Or it could be in the past; forget the future.

The current scenario allows for the diplomatic house upstairs, small office stuff, and elevators that descend down into levels downstairs, including lockers, bunks, trams to elsewhere, descent into a lower level, archive and control centers, and more.

I want to wrap it around something and that's where I come up short. It's been suggested an alien encounter, serving as a current or past oracle, but I'm not a big fan of that direction.

Any ideas?