The PCs enter a once thriving town, gone stagnant by random murders, and now showing little that would suggest any economic success. The murderers always comitted a string of as many as twelve murders, each occuring one night after the other, and quickly lost their sanity as the days and the murders slowly accumulated.
Anyway, the PC’s enter the town and are asked to clear out a monster’s den, (just fodder to keep the PC’s there, make it as monumental as you wish) but whenever they sleep in-town they awake fatiuged and tired as though they hadn’t slept at all that night, and all people on guard duty fall asleep quickly. Furthermore, a new murderer is on the loose, but nobody knows who they are. After hearing a little about that, they are confronted in the tavern (if there aren’t any people in there at the time, or otherwise in a secluded place where few other people are) by a mysterious individual who refuses to give their name, saying that a name is a word and unimportant (but will accept any name the PCs want to call them), will speak in riddles, will never say “Yes” or “No” flat out, (but will refer to either as speaking clothed, as opposed to speaking naked) and will go on a tangent about instruments. (i.e., the PCs decide to call him bob
Bob: Do you use an instument, PC#1?
Bob: But you have a sword/axe/scythe. Is that not an instument?
PC#2: If you wish to call it so.
Bob: Ah, but if you slay someone with your sword/axe/scythe, is it your fault?
PC#1: No, it would be mine.
Bob: Are you an instrument?
PC#3: Of course not! He’s an elf!
Bob: How can you be sure.
PC#3: Because I know.
Bob: How do you know?
PC#3: Because I learn.
Bob: How do you know what you learn is true?
PC#3: I can’t, I assume.
Bob: So how can you know.
PC#3: You play an interesting game.
Bob: The game is my own.
PC#3: How do you know it is yours?
Bob: I do not know, I assume.
PC#3: So you cannot be sure of anything either.
Bob: Some Assumptions can be trusted.
PC#3: But how do you know which ones you can trust?
Bob: By assuming.
PC#3: (chuckles) So what if I am an instrument?
Bob: Then someone can play you.
PC#4: What do you mean, play?
Bob: When I pluck a string on a mandolin, it produces a note. When you swing your blade, it slices through that which you wish to have it slice through. How do you know you cannot be plucked or swung?
PC#5: We cannot, we assume.
Bob: So might anyone be playing you?
Bob: But might you know who plays you? Just as a Bard plays a lute, the strings might be tighter or more loose, he may leave fingerprints, the instrument may be mislaid, the instrument may be damaged. How can you tell if you are any of those?
PC#3: By watching.
Bob: With what?
PC#1: Eyes, of course.
Bob: Of course. However, I must be going. Farewell.(or similar closing)
(Later, PCs find a glass eye in their possessions and notice some cuts and bruises in places where they don’t remember- and where witnessess claim to have seen the murderer maimed)
etc.) The talk of instruments is generally to cover what the stuff in the parentheses is- The PCs are being manipulated by a powerful wizard who is trying to get rid of the populace (probably for ruins that lie beneath the town. He can have nobody see what he draws from what lies untapped below, so he removes the people in the town).
After that, it will take another conversation with the stranger to either find where the wizard’s (The stranger referes to him as a musician) hideout is, or to stay awake during the night. For the latter, they lie in wait for the wizard, chase him back to his hideout, etc.