A group of angry Fereldan refugees protecting Anders is waiting outside. Bethany or Carver can be asked to step in to diffuse the situation. A diplomatic Hawke can also get the refugees to back off peacefully with the "We're on the same side" option. All other dialogue options lead to combat.
Travel to Anders's Clinic in Darktown. Anders initially reacts to Hawke's presence with hostile uncertainty but after asking for a way into The Deep Roads, he proposes a favor for a favor. Anders explains that he came to Kirkwall to free his mage friend Karl Thekla, who is a prisoner in the Gallows. Help Anders bring Karl to safety, and he'll provide Hawke with Warden maps of the Deep Roads.
Meet Anders near the Kirkwall chantry in Hightown at night and head inside. There is a Codex entry: The Maker up the stairs in the middle, and a Crate in the southwestern room. Karl can be found on the opposite side, to the right of the entrance. He had been made Tranquil and set up as bait. Anders is enraged by what has been done to his friend, and as the party is attacked by the templars, the spirit of Justice overtakes him.
The initial wave consists of:
Templar Lieutenant (Elite) – drops Ser Alrik's Letter - this must be looted quickly, as below
3 Templars (Normal)
1 Templar Archer (Normal)
Once most, if not all, of the normal ranks are defeated, a second wave appears:
Templar Hunter (Elite) – drops random loot
2 Templars (Normal)
1 Templar Archer (Normal)
The corpses must be looted before all enemies are dead and the cutscene begins.
Once the templars have been defeated, Karl becomes himself long enough to ask Anders to kill him rather than let him live as one of the Tranquil. No matter how you advise Anders, he will fulfill Karl's request. The party is automatically transported back to the clinic where you can learn more more about Anders's unique condition. Codex entry: History of Kirkwall: Chapter 4 can be found to the left.
Varric: friendship (+5) ps3 (May not happen after the 1.04 patch).
Using the diplomatic option "We're on the same side" available to a diplomatic Hawke:
Bethany: friendship (+5)
Carver: friendship (+5)
Aveline: friendship (+5)
Varric: friendship (+5) xbox360
"Back off.":
Aveline: rivalry (+5)
Bethany: rivalry (+5)
Carver: rivalry (+5)
When speaking with Anders for the first time, choosing to investigate and selecting the "Help him escape the Circle?" option:
"The mages need their freedom.":
Fenris: rivalry (+10)
"That's a little controversial.":
Fenris: friendship (+5)
"Mages must be contained.":
Fenris: friendship (+10)
When speaking with Anders for the first time:
"I help all my fellow mages." option as a mage:
Carver: rivalry (+5)
Fenris: rivalry (+10)
"You want me to fight templars?"
Fenris: friendship (+5) (this does not appear to work after the update) (works on PC 1.04, with investigation)
Bethany: friendship (+5) Bethany will comment (Approval increase requires also choosing the previous helpful/humorous response, "Yes."/"What's the favor?", also as of 1.04 PC version there is no friendship increase from Bethany from this.).