Find the prisoner and free him.
Much harder than Dust & Blood. In fact, your first attempt may last only a few seconds. People in trouble can 'cheat' using Dmute to boost the characters.
Unlike Dust & Blood, the prisoner scenario is closer to CSB than to DM. I wish I added more ambiance elements but I started this dungeon 6 months ago and really wanted it to be released asap.
Have fun !