The penultimate Martin Beck novel is about contrasts and the changes in Swedish society since the series began. Martin Beck, now head of the National Murder Squad, is called to sleepy part of the country to investigate a woman's disappearance. What Beck doesn't know is that the woman has already been murdered, her body dumped in a swamp.
As Beck hunts for clues he comes under pressure to arrest Folke Bengtsson, the killer he put behind bars in Roseanna, the first novel in the series. Bengtsson has now been released and lives nearby. Beck doesn't think Bengtsson did it, nor does his partner Lennart Kollberg, indeed both men begin to wonder whether Bengtsson was guilty of the killing of Roseanna McGraw at all.
The media swarms over the little town and among the journalists is the man who was convicted of murder in the second novel of the series, The Man Who Went Up In Smoke. The presence of these two killers, one who may not be guilty at all and another who killed by accident, raises a theme from previous books: there are different kinds of murder and different kinds of guilt.
The idea of Sweden's decline is further explored when the action cuts back to Stockholm and a shoot-out between two young men and three policemen. One of the men escapes, shocked after his partner guns down two of the policemen before being shot dead. In a touch of irony typical of Sjowall and Wahloo, the two shot policemen survive but the third dies, stung by a wasp after he dives into a ditch to take cover.
The fugitive 'cop killer' will accidentally provide the solution to Martin Beck's murder case but that's not really important. What matters is the juxtaposition of the sleepy countryside with the violent city and the tension between the ever decreasing number of capable police officers and the growing number of incompetent or corrupt ones.
Kollberg increasingly despairs while Beck goes on trying to make what difference he can. The book has a surprisingly light tone, largely because of the addition of Hergott Allwright (called Hergott Nojd in Swedish - which I assume is a mildly comic name, just as Allwright is in English). Nevertheless, the good humour can't hide the fact that this is one of the bleakest novels in the series.