This was Milne's first and final venture into the detective and mystery genre, despite its immediate success and an offer of two thousand pounds for his next mystery novel. The story is set in the quaint, English countryside at the house party of Mark Ablett, where a murder quickly takes place.
Milne lets his readers inside the head of his amateur detective, disregarding the clichéd romance or violence of other detective novels, as the mystery becomes a puzzling sort of parlor game for the novel's characters and readers alike.