The following conversation ensues as Inspector Matthäi is taking his leave from the parents of a murdered 8-year old child.

Who is the murderer?” she asked in a voice so calm and sober that Matthäi was startled.

“I intend to find that out, Frau Moser”.“The woman just looked at him.  Her gaze was threatening, imperious. “Is that a promise?”

“It’s a promise, Frau Moser,” the inspector said, impelled solely by the desire to leave this place.

“On your eternal salvation?”

The inspector hesitated.  “On my eternal salvation,” he finally said.  What else could he do?

Almost but not quite casual.  Anyone would say the same thing in such circumstances but not everyone would feel bound to the promise, the pledge.  It is Inspector Matthäi’s tragedy that he does. 

The body of Gritli Moser has just been found in the woods.  The travelling salesman who had stumbled across her body is arrested as prime suspect and subjected to an arduous interrogation by Inspector Heinz, the new kid on the block, keen to make a name for himself.  When the salesman confesses and subsequently commits suicide, the police look no further.  Yet Matthäi, who was due to leave Switzerland to take up a prestigous post in the Jordan, is not convinced and mindful of his promise to Frau Moser, determines to stay to find the real murderer.  Only he can’t do it from within the force – he had resigned his post to transfer to the new one – and his refusal to take the new job has caused political ructions.  There is no way he will be reinstated.

Matthäi is convinced that he has a serial killer on his hands.  Gritli Moser bore a remarkable ressemblance to the victim of a previous unresolved case.  He has made that promise.  One that proves to be the seed of an obsession that will mark the man for eternity.  His  personality changes.  He begins to drink.    The only real clue he has is Gritli Moser’s drawing of a giant and lots of hedgehogs. A bachelor used to living in hotel rooms, he buys a run down petrol station on the main road to Zurich and installs a housekeeper with a young daughter. 

Matthäi’s story is told by his ex-boss the chief of police who hasn’t a clue what he’s up to.  Until the following conversation.  

“Remember the trout needs prey, he’s a predator.  The first thing you have to figure out is where the fish likes to be.  Naturally that would be a place that’s protected against the current, but near a strong current, because that’s where a lot of animals come swimming along …”. “And the bait?” I asked.  “Well, that depends on what you’re after, a predator, or a grayling, or a burbot, which are vegetarians,” he replied “A burbot you can catch with a cherry.  But for a predator like a trout or a bass you need something that’s alive.  A mosquito, a worm, or a little fish.”

It is apparent that Matthäi is playing unethical games with high stakes.  Yet it appears that these are destined to succeed, the true murderer will be entrapped and Matthäi will be released from his promise.

Life though doesn’t always go to plan and even while it is proving Matthäi a genius, attuned to realities that others cannot see, it is undoing him.  Matthäi’s ex-boss is keen to make that point to the author of somewhat generic crime novels in a  framing device which turns the whole into a metafictional treatise on crime writing. (Something that I would have realised sooner, had the novel’s subtitle, Requiem of the Crime Novel, not been entirely missing from my film tie-in edition.)  In life, ends aren’t always neatly tied up.  Sometimes the worst thing that can happen does. At other times the ending is thoroughly shabby.  An excellent crime novel, he argues, will show this authentically.  By that standard The Pledge is exceptional.