Everything was solved at the end of the first season, but it lasted for twenty episodes. It does drag a bit, but for the most part, I loved it. I've actually started watching it again as it's on LoveFilm Instant which I subscribe to.
There was a second season in 2009 which ran for ten episodes. I enjoyed it, but not quite as much as the 1st. Still edge of your seat viewing though.
I read the other day that a 3rd and final series will air in Denmark in September.
http://www.youtube.com/watch?v=4IZUWkghFeQ