My wife and I are slowly working our way through the delightful Poirot TV series, starring David Suchet. Last night we watched Double Sin, but had a nagging feeling of familiarity; we wondered if we had seen a different dramatization of the same basic story.
Poirot and Hastings, on a bus trip north, make the acquaintance of a young girl who is couriering a set of valuable cameos to a prospective buyer. They arrive, and the girl announces that the cameos are missing from her suitcase!
The buyer is found, and he says that he just purchased the cameos, apparently from the thief! It develops that the owner of the cameos, in cahoots with the courier, faked their theft and sold the cameos to the buyer posing as the thief, hoping to end up with the money and the cameos, reclaimed as stolen property.
Subplots include the red herring of a novelist secretly eloping with an aristocratic lady, and Poirot secretly watching a lecture on detection by Inspector Japp, with results gratifying to his vanity.
So the question is, has that story ever been filmed with a different cast?