This book was so boring over the first third I thought I might have to kill myself. Then it improved somewhat, only to go to hell over the last 15% or so. The 3* rating should have a - [minus] appended.
So, it's a Poirot story as told by Capt. Hastings. It seems that a very rich man, M. Renauld, is fearful and writes Poirot to come to France to get/keep him out of trouble. But when Poirot and Hastings arrive at the man's villa, he is found to have just been murdered. He's lying in an open grave out on a golf course with a paper knife sticking into his back.
So, the suspects pile up. Perhaps the son, Jack, perhaps the jilted lover of Jack, Bella Duveen, perhaps Mme. Renauld, perhaps a gang of masked thugs, .... It seems that M. Renauld has a sketchy past and has recently begun to be blackmailed by the woman in the villa next door. Apparently they have some secret together buried some 20 years in the past. The woman's daughter has bewitched Jack, so perhaps she's involved. Or, perhaps the private secretary. It could be anyone. Then to make things more fun and confusing, there's a French policeman, M. Giraud, who is full of himself and who goes out of his way to insult M. Poirot. Given that Poirot is one of the world's supreme narcissists, that doesn't sit well, and M. Giraud must be taught a lesson.
Anyway, as you can tell by this garbled mess of a review, the book is rather a garbled mess. When it's not boring you to tears, it's tossing in all kinds of weird coincidences and improbably red herrings. I dunno. I didn't care much for this and will probably avoid Christie for a while. To be fair to Christie and Poirot, I have rather enjoyed the videos my spouse makes me watch with her.