What appears to be the central crime is fairly typical stuff, but Christie lays red herrings profusely across the reader's path. Indeed they're essential in this novel as the murder turns out to be a whole lot more complicated than it initially appears. One of the cleverest elements in this novel is a crime that is barely incidental to the plot - one of the cleverest fictional murders I've ever come across (although I'm not entirely sure whether it is actually possible), and she just throws it away in such a casual style. A truly assured Queen of crime.
So the basic elements are all there - it could be fantastic. And yet....it doesn't quite gel. The characterisation is pretty weak here - not that you would expect fabulous characterisation in Christie, but it is unusually paper thin. There's a dreadfully weak romance thrown in at the end, which doesn't feel convincing, or add anything particular to the novel. And there's an odd feel overall to the book - it feels like a stage play : the setting, the dialogue, the movement of the characters, it just all feels to me as though this was intended to be a play, and for some reason was changed mid-course to a novel, which could account for a lot re the missing elements within the book. It's not the best of Christie, but it is a clever tale. Would be a good postscript to viewing a Christie classic such as Witness for the prosecution.