You don't really have to read this. Just screw up your eyes and imagine snow; Harry Hole in dire straits and not wanting to do police work, but getting called back anyway because there's another serial killer on the loose; despite being half stoned and half drunk he outperforms the entire police force and the Kripos (which I think is the Scandinavian equivalent of the feds); more people are killed in horrible ways; HH goes through painful excitement and gets his man... except of course he gets the wrong man at first... and then he realises that he's got the wrong man and gets the right one instead. Just.  And at the end, he gives up and disappears again, having won numerous small internal battles en route.
   Yep, you've got it. It's formulaic, but that doesn't make it a bad book. If you like following the antics of Harry Hole chasing serial killers while everyone else seems to have a combined IQ of about 10, then you'll enjoy this one as much as you've enjoyed the others.