While trekking in the mountains I came across wethyl fortress this put Kvatch rebuilt underground quest automatically into my journal, now, finally I have Kvatch completed I am count and the castle is fully open to me. How do I start this quest? I have looked everywhere and spoken to most everybody I just can't find a way to start it. It is about a month ingame time since I became count of Kvatch.

I would appreciate it if anyone can help.