Three single girls share a London flat in 1965. The first works as a secretary; the second is an artist; the third, who comes to Hercule Poirot for help, disappears believing she is a murderer. There are rumours of revolvers, flick-knives and blood stains. But, without hard evidence, it will take all Poirot's tenacity to establish whether the third girl is guilty, innocent or insane.
Ariadne Oliver also appears in this novel.