The second in the FFSG series.

The peace and quiet of the little town of Wellbury is slightly ruffled by an interview on the local radio of Professor Jonathon Humphries in which he predicts a coming cull of the population by up to eighty-five-percent. In his book, "The Coming Wave" he has described how the cull will be a natural result of Mother Nature defending herself against over-population. It will begin with those less useful and more disliked, and, as a natural phenomenon, nothing can be done to prevent it.

Initially sceptical, Detective Sergeant Frank Summers and his boss Detective Inspector Frieda Garold are slightly alarmed at the way their colleagues seem to rally to the idea. And the day is not out before the first victim bearing a note "85%-1" is found, an elderly neighbour nicknamed Nagness for the hectoring tone which she adopted towards any who came into contact with her.

A day later and it's the turn of a traffic warden. Then an estate agent. As the body count mounts Frank attempts to isolate the potential perpetrators. They range from a local councillor who is a born-again Christian, through the editor of the local Herald, to a vicar and his apparent minder, a stream-of-conscious speaking Mrs Blower.

Frank makes a break-through when he realises that the murders are following a list of "the top ten most disliked" which had appeared in the local Herald not long before. To the disgust of Frieda's arch rival, Percy Hanson, the police have only just scraped in at number ten.

Engrossed as ever with the curious, Frank fails to notice that his spare time is actually being regulated by three women who have adopted a strange habit of calendar watching; his boss Frieda, his constable Giggling Gertie, and his on-again, off-again, angry-again, sort-of girlfriend, the pathologist Susan "Dr Death" Pleadle.

What initially begins as a bit of boyfriend time-share fun develops into a personal bodyguard as the count increases towards the magic ten, and the police officer likely to be the target is the person investigating the case. While the women might joke that, if Frank is going to be killed they will be the ones doing it, it turns out that there is an excellent chance of that being the exact outcome as they race around a Wellbury becoming increasingly gridlocked by citizens taking their own action against those they consider to be "Eighty-five-percenters".