Original Airdate: 16 September 1990 Written by: Clive Exton Directed by: Ross Devenish Recurring cast: Captain Hastings, Inspector Japp Based on:The Mysterious Affair at Styles
Tropes
Adaptational Angst Upgrade: Hastings is implied to be suffering from shell-shock; the book only brings up his physical wounds.
John Cavendish has his attempts to make Mary jealous with romantic entanglements greatly downplayed, and Mary's similar Operation: Jealousy is removed entirely by virtue of Dr. Bauerstein, whom she used for it, being Adapted Out.
Likewise, Lawrence's extreme (and completely groundless) jealousy of John and Cynthia isn't shown, and in general his aloofness towards Cynthia is only spoken about by Cynthia herself but never appears onscreen.
Adaptational Job Change: In the book, Lawrence is an aspiring writer who has previously studied medicine but never worked in that field. Here, he is a doctor and working at the same hospital as Cynthia.
Adaptation-Induced Plot Hole: A minor case. In one scene, Hastings and Poirot discuss about the case suspects, and Poirot points out the suspicious manner in which Lawrence insisted that his stepmother's death is either due to natural causes or an accident, rather than murder. Hastings dismisses this oddity as a common layman mistake, until Poirot reminds his friend that while Lawrence is not a doctor, he has a medical degree and is thus qualified as one. While this is true in the books, in the series, Lawrence is a medical professional.
Catapult Nightmare: Hastings dreams of being run over by a tank and wakes up with a start – only to hear Mrs. Inglethorp's dying screams.
Death by Adaptation: Mrs. Raikes is a widow here; in the book, her husband is still alive.
Feet-First Introduction: Poirot gets one. We see a close-up of his walking patent leather boots and hear his voice as the camera moves up from his legs until it gets all the way up to his face again.
Origins Episode: The episode was aired as the first episode of the third season, making it an example of the trope.