I think this would have done better as a short story since the truth of what happened was easily guessable and then obvious once it was revealed that Margaret had a twin. The lack of many characters to suspect made it easy and a bit boring. Although I do love Ariadne doing her investigations and interviews, it felt so Miss Marple. I will say that the ending was one of Christie’s saddest endings and I did feel dewy-eyed reading it.