Demands of the Qun

Late in Act II, return to the Hawke Estate to find Isabela and Aveline arguing, both needing your help. Isabela reveals that she has found the relic that she lost. This also means that her pursuer, Castillon, would spare her life once the relic is returned.

Acquisition
Enter Hawke Estate at Hightown, and choose to help Aveline first to immediately activate this quest, this will cause Isabela to Permanently be removed from your party. If you don't want to do that then choose to help Isabela first and follow the To Catch a Thief quest. After you complete To Catch a Thief you will receive this quest.

Walkthrough
...

Result
...