Lit only by scattered torches, The dungeon lies far underneath the castle.  Bandits and Thieves who find themselves there are met with cold stone walls and floors, with chains and bars restricting movement.  Guards patrol the corridors, keeping an eye out for any escape attempt or misdeed.  The only comforts afforded in the Dungeon are the piles of hay for sleeping.
Dungeon, Inside Castle
spider
guard
I am a king's guard in the royal palace. I am fighting against the army trying to overthrow the king. I am a guard who has pledge my life to defend the king.
Oh, well hello little spider friend! Do tell! Do you keep watch for flies as I keep watch for thieves?  Yes, yes I do! I love eating unwary prey, and not just flies.  Wh-what is this?! You can talk?... no. No, no, no! I have been down here too long! My mind is wandering again... Either I can talk ,or you are going crazy! ...i-indeed! Oh, Mr Skeleton?! Are you hearing this? No? Well I must be crazy, then! *spins web* What? What do you mean the spider is making a monkey out of me?! You have always been so RUDE, pal! Gosh, how long have you been down in this dungeon? Wait... how would something I imagined not know that? Oh, god! How long HAVE I been down here? Way to along. I have watched for for quite some time. Stop sleeping on that hay! IT is filthy Oh... perhaps you are right, spider friend. I... I thought someone was to relieve me of my duties by now.. I afraid to tell you that they are dead sir, they skeleton that you were yelling at. Well...