When you go to Aldanon's mansion in Blacklake (N3-8) it will turn out that it's been attacked by bandits. Cormick is being held near the entrance as a hostage. Try to negotiate his release - you can fight them or ensure them that they will be free to go if they agree to cooperate. Talk to everyone and go inside. There's a bunch of bandits around the house to be defeated - clear the whole level and go to the basement using the western door.
In the cellar you'll see the bandits' leader and the rest of his hostages. Defeat all hostiles around and talk to Aldanon's servants. His master has been kidnapped. Go to Castle Never to tell Nasher about this. He'll give you a quest of ensuring the safety of Lord Tavorick. Also, talk to Nevalle to receive a short side-quest concerning a tailor named Larim.