A rusty/Terran/alien/ancient/unreliable/cutting-edge (delete as appropriate) space station in deep space/orbiting a dead world/guarding an alien planet (delete as appropriate).
You’re a team of Earthers/natives/aliens/robots (delete as appropriate) charged with handing it over/taking it over/scuttling it/repairing it (delete as appropriate).
But as ancient forces/political factions/hostile aliens (delete as appropriate) unexpectedly come into play, suddenly you’re at the epicentre of an epic struggle which could change the future of the entire galaxy. (No alternatives on offer).
I’m going to come along with LOADS of plot fully prepared to rip it up in favour of what the players come up with. The only things I’ll not allow on the table are peace and safety.