The PCs are likely are going to try to get into a safehouse of the local thieves’ guild in the next two sessions. The setting is Ptolus, using the D&D 5E rules.
The safehouse in question is in a lower middle class region on the surface, but it has another entrance to the vast dungeon systems beneath the city. This, in itself, is not unusual - the bedrock on which the city stands is filled with tunnels and long-forgotten vaults. But while most house owners just try to brick those passages over, the thieves’ guild actually uses these passages for their business dealings.
And I need some ideas on both what might be inside the premises, and what kinds of systems they use to secure the safehouse. The PCs will likely be coming from the “dungeon” side, and this is the kind of city where criminals expect inconvenient adventurers to pop up in all sorts of places.
I’ve already determined that the location includes:
- a vampire ally of the guild
- some cells for prisoners who get interrogated for information
- a bunch of drugs for resale
Any other ideas? The party consists of four 8th level characters, if this helps.


@juergen_hubert It makes me wonder why there are so many tunnels to begin with. Of course, in a fantasy world they could just be a side effect of unusually large worms, or something.
But first thing that comes to mind is catacombs - if not the primary purpose, a secondary usage. So walls lined with bones is maybe something?
The city of Ptolus has a long and convoluted backstory, and is known across much of the continent as “that weird city with all the dungeons and adventurers”. Suffice to say, there are reasons why the region attracts all kinds of supernatural creatures, and there were many, many different groups of people and creatures who expanded these dungeons.
If you like the whole concept of “dungeon delving mixed with city adventures”, I can highly recommend Ptolus. Few do it better, or more exhaustively.