The club in question is made up of four residents at a retirement village. They start out by speculatively investigating cold cases that a former member, who had been a police officer, had records of. But soon a hot case lands right in front of them, and things get interesting.
It’s hilarious in places, moving, well-plotted, and, let’s face it, a tad unconvincing. But you don’t let that bother you while you’re reading it.
Which you should do.