The latest Harry Hole thriller and he is out of the police force and lecturing at the Police college. A number of loose ends from earlier stories are tied up here so it is an advantage, although not essential to have read the earlier novels. Harry's old team are on the hunt for a killer who is targeting policemen and women with a connection to a old crimes which were unresolved or had some difficulty about them. Harry's personal life is finally getting to a point where he asks Rakel to marry him but will his commitment be derailed by a troubled student seeking to seduce him while he solves another 'unsolvable' mystery? Red herrings aplenty which is no doubt appropriate for a Scandinavian mystery. Excellent stuff!