If you want to leave DoubleAK a tip for writing this Dragon Age 2 guide you can do so here.
Dragon Age 2 Walkthrough Act 2: To Catch a Thief
Dragon Age 2 Act 2: To Catch a Thief
Return to Hawke's Estate in Hightown to find Aveline and Isabela waiting for you. Make sure Isabela is in your party before you proceed to Lowtown (Night) to begin the quest in earnest. The streets leading to the hideout are loaded with Dog Lords.
Isabela will ask what you intend to do with the relic before heading into the hideout. You can tell her that she's allowed to take it to her pursuer or that it's going to the Qunari, but either way she will be leaving the party for a bit. Your tank, mage and damage-per-second attacker of choice will have to do the heavy lifting in the warehouse.
Isabela will depart as soon as you enter the warehouse. Try and snipe the Qunari spear throwers lurking near the stairs as well.
The Sten is by far the toughest of your foes and should be left for last. Have your tank draw him him while your DPS character strikes down the weaker foes. If you find yourself losing health too quickly, then don't be afraid to drink a few Health Potions