The Exiled Prince | Premium content Dragon Age II Guide

Received from: Automatically after installing The Exiled Prince DLC

In order to receive this mission, which is connected with a chance of gaining a new party member, you need to have The Exiled Prince DLC. What's curious about this mission is that unlike other companion quests that appear in given moments of the playthrough, you will have a bit more freedom here. You can approach this mission as soon as finishing the Destruction of Lothering, that is after reaching Hightown for the first time. Of course nothing stands in the way of beginning this quest a bit later, that is during Act II. Irrespectively of when you start it, head to [Hightown]. Head to the board of the Chantry Courtyard (M3, 17) #1 to witness a conversation between Sebastian Vael and Grand Cleric Elthina #2.

Approach and interact with the board #1. On the list you should find a position marked as Duty #2. Read the message and press Accept to start Sebastian's mission. On a side note, you can talk about Sebastian with Grand Cleric Elthina, found in the Chantry's building. She can tell you some interesting facts.

Unlocked premium content quest: Duty