It's December 19, 1931. Hercule Poirot and Inspector Edward Catchpool are looking forward to a much-needed, restful Christmas holiday, when they are called upon to investigate the murder of a man in a Norfolk hospital ward. Cynthia Catchpool, Edward's mother, insists that Poirot stay with her in a crumbling mansion by the coast, so that they can all be together for the festive period while he solves the case. As Poirot digs into the mystery, he discovers...

Now retired and living in self-imposed exile in the world's most glamorous city, Poirot reluctantly attends a séance at a decaying, haunted palazzo. When one of the guests is murdered, the detective is thrust into a sinister world of shadows and secrets.

Hercule Poirot investigates a string of murders that appear to be disconnected on the surface, but for some obscure reason that Poirot is determined to uncover, the number four keeps popping up with every killing. This collection features the original linked Hercule Poirot stories as they first appeared in The Sketch periodical, before Christie re-worked them with her brother-in-law to create the novel, The Big Four.