The book starts with the narrator travelling to Chur in Switzerland to give a lecture on the art of writing detective stories. The talk is not a success, and the writer meets Dr. H., a ex-chief of police in the canton of Zurich. Dr. H offers to drive the writer to Zurich. On the way they stop at a gas station. An old man is sitting on a bench outside: “unshaven and unwashed”, smelling of alcohol and wearing “dark, grease-spotted trousers that had once been part of a tuxedo”.

After they leave, Dr. H. tells the writer that the old man, Matthaï, was once a brilliant policeman who didn’t smoke or drink. Some years ago, he was assigned to travel to Jordan to help reorganize the police there. Just a couple of days before he was due to leave, a call came from Mägendorf about the murder of a child, Gritli Moser. Matthaï was asked to lead the case until his departure.

Matthaï interviews the parents and is about to walk away, when Mrs. Moser makes him promise that he will find the murderer. Wanting nothing more than to get away from the place, Matthaï makes the promise, not really intending to keep it. But when he gets to the airport to catch his flight to Jordan, he has a crisis of conscience and turns back. He had made a promise to the mother, and he intended to keep it.

Matthaï throws himself into the case. He is convinced that the killer is not a local but a serial killer operating in the area. He sets out to lure him into a trap, using any means available. He goes against procedure and his superiors. He is eventually taken off the case but cannot let go. Slowly, his obsession destroys him, until he becomes the half-crazy wreck sitting outside a gas station.

This book is tautly plotted and fairly grim. There are no neat resolutions, just messy endings. Friedrich Dürrenmatt uses language economically and creates a sense of oppression. When he describes Chur and northern Switzerland in the winter, it is no winter wonderland: Chur is covered with “dense, sluggishly lumbering, snow-filled clouds” through which you could see a “patch of metallic sky”. A snow-covered valley is “rigid with cold.” His description of Matthaï’s gradual breakdown is compelling.

This book was made into a film with Jack Nicholson. Even if you have seen the film, you should read this book—it is better than the film.