Cyrodiil/A Stormcloak in Chains

Quick Walkthrough
# Talk to   about his interrogation worries.
# Interrogate  .
# Beat back the Stormcloak assault and decide whether or not to hand Bjarni over to the Penitus Oculatus.
OR
# Break Bjarni free from his cell and lead him outside.
# Slay the Legate and the Penitus Oculatus agents and escape the fort.

Detailed Walkthrough
A Sullen Stormcloak
Upon arriving at  , you will witness a soldier delivering a report to  : the recently captured   has not been cooperating with interrogators. Ask the Legate about this and he will reveal a Stormcloak was caught crossing the border from Skyrim but that he has proved utterly cooperative under questioning. If he can't get the prisoner to talk soon, the Penitus Oculatus, who are on their way, will. He asks for your help and sends you off to the prison with a  . 

Once you arrive at the  , the guard will check your letter and then open the door for you. All exterior doors leading outside will now be locked right across the fort, the main entrance door being the only exception. Head inside and make your way to the cell holding Bjarni Shatter-Stone, the Stormcloak prisoner. From here, you can take two routes: either helping Bjarni escape or aiding in his interrogation.

Enhanced Interrogation Techniques
thumb|right|Off to Blue River Prison
When first speaking to Bjarni, his cooperation will depend on how you approach the conversation. If you claim to be part of the Legion or question him with a low Speech or Illusion skill (below 50), he will brush you off. If you do possess good interrogation skills, or if you simply trick him into thinking you're a Stormcloak, he will confess his plan: invade Cyrodiil and strike at the Imperial City, the heart of the Empire. At this point, the   approaches and asks for a quiet word in his quarters: he wants you to keep pressing the prisoner to find out who sent him and how many accomplices he has.

Extracting both pieces of information will require even higher levels of Speech or Illusion: a minimum 75 for the former, and 100 for the former. In addition, persuasion will not work when asking him about where his orders came from. Eventually, Bjarni will admit he's part of a splinter group, the Stormcloak Breakaways, and that he made his way through the   along with six other companions. Report back to the jailer, and you will hear a commotion in the cells; rush back to find a Stormcloak soldier trying to free Bjarni. Dispatch him and head back into the fort to warn the Legate, battling your way past a number of Stormcloaks. 

Once outside, help the Legate defeat the Stormcloak assault party and witness the arrival of two Penitus Oculatus agents, who will ask you to share all your information with them. If you refuse, they will attack you. If you agree, Bjarni will be brought out in front of them and plead to you to rescue him. If you decide not to intervene, the agents will teleport away with the prisoner; alternatively you can attack the agents. In both instances the fort garrison will side with you. Regardless of your choices, Varro will reward you with 600 gold.

Pale Pass Redemption
thumb|right|I'm not angry, just disappointed...
If you instead decide to help Bjarni, which you can do at any point until your final set of interrogation questions, he will ask you to steal the   to the cells from the table in the jailer's quarters and open his cell door. Once he is free, he will immediate fight and kill the jailer. You can now choose to either attempt a sneaky exit from the fort, or go for a full-blown prison break. 

If you choose the former, it is better to wait until night time, when most of the fort will be asleep, and to avoid freeing the other prisoners. If you're going for the rampage option, then freeing the three other prisoners and providing them with equipment from the nearby armory is advisable. Regardless of either option, breaking into the Legate's private quarters and blowing his   from the top of his tower is also recommended, as it will provide you with a reinforcement of three Stormcloak soldiers to aid you in the final confrontation.

Once you step outside the fort, you will be met by the Legate and two Penitus Oculatus agents, flanked by a number of other soldiers. The Legate accuses you of being a traitor and will then proceed to attack you. This is a tough fight, in particular the Legate and the agents will provide stiff resistance, so having the extra reinforcements and the other prisoners can be of great value. Once the Imperials are all dead, Bjarni will say his goodbyes and ask for your name. If you give it to him, a few days later you will be approached by a courier with a   from Bjarni and 500 gold.

 

Notes
While the quest objective will simply tell you to escape the fort in the event you choose to stage a prison break, simply running away won't do - you will need to kill all Imperial soldiers before the quest can be completed.
If you chose to help Bjarni, after the quest is complete the   will be staffed by Stormcloak soldiers, rather than Imperial ones.

Quest Stages