I had previously watched a bit of Season 1, but plot was too similar to the original, which took the suspense away and I dropped it. I then saw that they had a Season 4 and decided to give that a go, as the Danish version only goes to S3.
It resumes with Linden (Lund) having killed 'someone', presumable at the end of Season 3 (like in the original), except they're trying to get away with it.
The 'killing' that they're investigating is taking a long time to get going, but is now ramping up and meanwhile one of their colleagues is suspicious of them.
My only real issue is Holders accent. It sounds like a bad Danish accent, but then I only just found out that he's Swedish/American which may explain it... I'm sure it wont bother non-Danes.
Definitely worth watching...