As long as you don't have your battle tower yet you'll be able to do it.
You get the quest from the guy in the barracks building in broken valley town. The guy talking to the woman you came with. He tells you about his plan to find the bandit camp and a secret passage to get into the cell to free the guy to put his plan into motion.
Ah ok I freed the guy from his cell using the underground passage from the burned downed church area entrance now only an exit.
Oh since you seem very knowledgeable about the game I have one piece of parchment not sure where I picked it up from, but from ready the forums I need a total of four but not sure where the are all located. I think I got the one parchment from the area out side the bandit camp, but not sure looking around atm for them....
