This whole chapter walks away a little from the main storyline. It lets you find out more about yourself and about Alvin, as well as finally catch up with Berengar.
Saved by Triss from Adda's kiss (and death, but that's less important), you are teleported to the Lakeside. The cult of underwater gods is much stronger around here - in fact, they're quite present themselves. Ask the nearby girl about the situation, she'll help you find yourself in this new setting.