You have to talk with six npcs: In Aldlyn, Ebron, Parverhill, the Red Keep, Thremten
and in Witton. But you must have Mirel in your party already.
In Ebron talk with child, in
Witton talk with person near snowman, in Parverhill talk to lonely
woman in empty house, in Thremten talk with green-haired man, in Red
keep talk with sleepy guard near tent, in Aldlyn talk the visitors of
the Inn.
It's also necessary that you had the events with Mira and Mirel at the festival of Thremten and that your relationship with them is high enough.
If all conditions are fulfilled you can go to the top right corner of the Calbridge Stronghold, pass the gamble on a small mountain path, and press the action button on the tile directly on the border of the map.
