Someone gets arrested and thrown into the local city prison/oubliette. Maybe it's one of the PCs. Maybe it's our old friend Rosa Patrina, who was falsely accused of stealing, and it may happen that the local authorities may not believe the PCs when they spin a silly-sounding tale of sentient thieves tools...
No matter who has been locked up, the other PCs hear that nasty, mind-f*** torture is the rule of the day in there, so they're motivated to get him or her out by whatever means necessary!
What should they do? The PCs should be allowed to brainstorm to their hearts' content, but at least some of the following movie and TV tropes should come to mind...
- Conk a few guards on the head, steal their uniforms, and infiltrate the place in disguise?
- Get themselves arrested, while somehow smuggling in a bag of holding with their weapons in it?
- After gathering information about the movements of the guards (via either surveillance or bribing/charming a guard), go in at night ninja-style and take advantage of weak spots?
- Dress up as lawyers, judges, or chaplains and demand to see the prisoner?
THE PLACE ITSELF:
The layout should be easy to map out schematically, since most of it consists of long rows full of cells, punctuated the occasional guard room, torture chamber, kitchen, and so on. A simple "ball-and-stick" type map (like diagrams of molecules) may be all that you need to keep things straight.
RANDOM GUARD GENERATOR:
"You come upon a guard." What kind? Roll 1d10 for rank/class:
1-3: Newbie: level 0 "normal man" (1d4 hp), with short sword.
4-7: Regular grunt: level 1 fighter (1d10 hp), with short sword and dagger.
8-9: Sergeant of the guard: level 2 fighter (2d10 hp), with long sword and dagger.
10: Warden's special elite guard: level 3 fighter (3d10 hp) or level 4 thief or assassin (4d6 hp), with a more creative weapon choice. :-)
Then roll d10 for build (and adjust ability scores accordingly, if needed):
8: tall & thin
9-10: huge freakin' hulk.
And roll another d10 for the guard's overall sympathy to prisoners:
1: Hates all prisoners, but won't deign to abuse them ("I'm better than them.")
2-4: Hates all prisoners, and takes every opportunity for sadism towards them.
5-7: Completely neutral; just here for a paycheck.
8-9: Somewhat sympathetic; will help a prisoner out if he won't get caught.
10: Johnny Cash; will help a prisoner whenever and however he can.
WHAT'S THAT RANDOM GUARD DOING RIGHT NOW?
Roll one more d10...
1: Standing at post.
2: On regular walking patrol.
3: Chatting with his friend.
4: Bringing food/water to prisoners.
5: Going to get a prisoner for torture.
6: Bringing back a prisoner from torture.
7: Bringing in a new prisoner.
8: Slapping around a prisoner.
9: Gambling with buddies.
10: Waiting for accomplice in contraband trade.
WHO OR WHAT IS IN THAT CELL?
Roll a d20 this time:
1-9: It's empty.
10: New prisoner; a commoner who still has hope of release.
11: New prisoner; a royal who has no idea why they're here.
12: Town drunk; in and out 3 times a week.
13: War prisoner; captured battlefield enemy or spy.
14: Dead body of prisoner that nobody has discovered yet.
15: Long-term prisoner; exercises a lot.
16: Long-term prisoner; homicidal to anyone who comes near.
17: Long-term prisoner; catatonic (or other randomized insanity) due to torture.
18: Long-term prisoner; weasel-like snitch who knows the dirt on everyone.
19: Random monster being kept here because nobody know what else to do with it, and someone ordered it not be killed.
20: Noncorporeal spirit of a deceased prisoner.
WAIT... WHAT? A SPIRIT?
Entry 20 above was included because I wanted to give my own take on why there are different varieties of non-bodily undead. Well, that and because encountering a ghost in an already scream-filled oubliette is going to make for one memorable session!
Feel free to use the standard stats and powers for the creatures with the following names, but I think the alignments and origin scenarios may make more sense than what's in, say, the 1st edition Monster Manual...
- GHOSTS can be of any alignment; they had major unfinished business when they died. [POLTERGEISTS are just mischievous ghosts.]
- WRAITHS were either neutral or evil when alive, and they seethed with such envy and jealousy for others that it continues beyond the grave as a ravenous envy of the warmth of the living. [BANSHEES are variants of wraiths that use mainly sound to attack/scare the living, rather than their horrific appearance.]
- SPECTRES were pure evil humans, and their hatred for good was rewarded/cursed (by some evil deity, devil, or demon) in the form of immortal yearnings to attack good living beings. [SHADOWS are the weakest spectres.]
FYI: twin media inspirations: (1) the episode of Avatar: The Last Airbender called "The Boiling Rock," and (2) the workings of the guild of torturers in Gene Wolfe's New Sun books.