A murder mystery role play (to put it in modern terms) turns into a real murder which for all practical purposes does not make any sense as the victim is a harmless girl.
I dare anybody to solve this one without waiting for Poirot to explain everything in the end of the book; all the clues are there, none of them is hidden. The plot is so complicated you will have my greatest respect if you do. I was lost somewhere in the middle of the book, until this time I was able to follow Poirot.
5 stars to one of the greatest mystery puzzle.