Danish police detective Carl Mørck (Nikolaj Lie Kaas) has been missing from work for longer than he should have been, and his colleagues in Department Q where he works are getting worried about him, knowing he has had trouble getting over his divorce and the way life is getting to him. But the department concentrates on cold cases, those hopeless ones where someone disappeared years ago and no one was ever found to explain their vanishing or be arrested for causing them, and Carl's right hand man Assad (Fares Fares) has just been alerted to a clue that may set them on the trail of a fresh mystery. A bottle has been found washed up on the coast, and there is a message written inside: written in blood...
The Department Q novels by Jussi Adler-Olsen were an international success story by the time the Danish film industry began creating big screen versions, very much fitting into the Scandi-Crime genre that had grown to dominate the burgeoning market for mysteries and thrillers in the paperback world (or hardback if you didn't want to wait a few months). Indeed, Adler-Olsen's work was a strong contributing factor to the achievements the Northern European writers were enjoying, though the film versions tended to be major hits in that region and more cult items elsewhere: this trilogy was broadcast on British television, with A Conspiracy of Faith bypassing cinemas altogether, for example.
Although the fans of the books had their own mixed feelings about the quality of the films, as was so often the case when you had your own ideas about what they should look like in your mind, generally they were well-received and this third entry was regarded by many as the strongest, shaking off the sense of a television film which had somehow escaped to the picture palaces that tended to dog the first two efforts. This felt far more like a movie, with the closest the series got to the sort of action sequences its rivals from Hollywood would have delivered, one tense (if improbable) setpiece on a speeding train leading to a chase through a hospital as the killer makes good his escape.
What was pleasing about these works was that the simple jumping off point - a missing person case that has gone quiet - could lead to numerous conclusions, and while the previous instalment had worried over institutional corruption in the wealthy class, it was religion they were more intrigued by here. Carl is an avowed atheist, and that, it is implied, has left him with a chasm of emptiness in his emotions since he cannot fill his need to believe in something that would help his troubled mind with the presence of his fellow humanity, not least the lack of love in his life that Assad notes and makes not so subtle moves to get his friend to start dating again. Assad's faith has proved a great comfort to him, in contrast, and he comes across as a far more contented soul as he becomes a rudder for Carl's spiritual flailing.
But religion is not all good, for they trace the message in the bottle to a remote region of Denmark where a Christian cult Carl and Assad initially take to be the Jehovah's Witnesses have settled. They're not, they're more like the Family or some other problematic organisation, and it seems their particular faith has left them falling prey to someone who will manipulate their unthinking tenets as a way of proving to them and himself that Satan is abroad in the land, all to bolster the need for a God to counteract this. The film left it ambiguous as to whether Carl or Assad was correct to follow their existence the way they did, as after all seeing the cult's methods of controlling its followers was far more sinister than Assad's more positive take on his theology (pointedly, he is no Islamist fanatic), though it was clear Carl did desperately want something to salve his conscience working with some harrowing circumstances in his job every day - though we can understand his rescue impulse assists him more than he realises. If there were contrivances that were farfetched, overall this held its plot and concerns together impressively. Music by Nicklas Schmidt.