Few know of this place, and far fewer know of its location. This is a good thing, for nothing wholesome comes from here.
How long they carried him through those back tunnels, illuminated only by the flickering of torchlight, he had no idea. Then light seemed to explode when they reached the massive chamber. All around, unbelievably large red crystals captured the light of the flames and seemed to multiply it.
The PCs are sent with a diplomat to another country to protect him and do his bidding. There may be some espionage, rescuing, downright bullying, etc. Could make a nice medieval, special operations background.