The Cornish Mystery is a short story by Agatha Christie which was first published in The Sketch in 1923 in the U.K. It the U.S., the story was first published in The Blue Book Magazine in 1925. The story was gathered and included in the collection The Under Dog and Other Stories, Dodd, Mead and Company in the U.S. in 1951. In the U.K., the story was not anthologized until it was included in Poirot's Early Cases in 1974.
A middle-aged woman, Mrs Pengelley, tells Poirot she thinks her husband is trying to poison her. Poirot believes her and travels to Polgarwith in Cornwall but arrives just hours after she dies. Poirot blames himself for being late and vows to bring her killer to justice.
(may contain spoilers - click on expand to read)
Hercule Poirot receives a visit from a Mrs Pengelley, a middle-aged woman who is afraid that she is being poisoned by her husband, a dentist. She has been ill after eating but her doctor states that she is suffering from acute gastritis. She and her husband live in Polgarwith, a small market town in Cornwall. She has no proof of the allegation, only that she only suffers when her husband is at home, not when he is away at the weekends and a bottle of weedkiller, supposedly unused, is half-empty. There could be no financial motive to suggest why Mr Pengelley should try to murder his wife but she suspects an affair with his young receptionist. Another resident in the house was her niece, Freda Stanton, but that lady had a row with Mrs Pengelley the week before and left the house after living there for eight years. Mrs Pengelley is vague as to the cause of the row but states that she has been told by a Mr Radnor to leave Freda to come to her senses. Radnor is described as "just a friend" and a "very pleasant young fellow".
Poirot and Hastings travel to Cornwall the next day and are shocked to find that Mrs Pengelley died half an hour before. Poirot interviews the dead woman's doctor, who at first denies that anything could be wrong but is then astounded to learn she had gone to London to consult the detective. Their last visit before leaving Cornwall is to Mrs Pengelley's niece. They meet Freda Stanton and Jacob Radnor and discover that the couple is engaged, and that the cause of the row between Freda and her aunt was the older woman's own infatuation with Radnor, a far younger man. The situation became so bad that Freda had no option but to move out.
Poirot and Hastings return to London but are able to follow events in the papers as rumour spreads leading to Mrs Pengelley's body being exhumed and traces of arsenic found. Her widower is arrested and charged with murder. Attending the committal hearing, Poirot invites Radnor back to his flat where he produces a written confession for the man to sign. He planned to get rid of both the Pengelleys, one through murder and the other by execution so his new wife, Freda, would inherit their money. Mrs Pengelley fell for Radnor because he made sure she would, flirting with her while at the same time planting seeds in the woman's mind that her husband was trying to poison her. Poirot offers him twenty-four hours escape if he signs the confession before he hands it over to the police and dupes the man into thinking that Poirot's own flat is being watched. Radnor signs and hurries out. Poirot confesses to Hastings that he didn't have any real evidence of Radnor's guilt and that the stunt was his only option to get Mr Pengelley acquitted. He is sure that Scotland Yard will catch up with Radnor, despite the latter's twenty-four hours start.
- Hercule Poirot
- Captain Hastings
- Mrs Pengelley
- Edward Pengelley
- Jacob Radnor
- Freda Stanton
- Miss Marks
- Dr Adams
Film, TV, or theatrical versions
Agatha Christie's Poirot
A television film with David Suchet as Poirot was produced as episode 4 of Series 2 of the ITV series Agatha Christie's Poirot, first broadcast on 28 January 1990. The adaptation is highly faithful to the original story.
- 1923: The Sketch, Issue 1609 (London), 28 November 1923
- 1925: The Blue Book Magazine, Vol. 41 No. 6 (Chicago), October 1925
- 1951: The Under Dog and Other Stories, Dodd Mead and Company (New York), 1951, Hardback, 248 pp
- 1974: Poirot's Early Cases, Collins Crime Club (London), September 1974, Hardcover, 256 pp; ISBN 0-00-231312-X
- 1973: Ellery Queen's Mystery Magazine, vol. 61 no. 3, whole no. 352, Mar 1973.