This Christie was a bit more convoluted than normal and so listening to the audio I really had to pay attention at the beginning to get all the facts and characters straight, but was transfixed thereafter. 

I followed all the twists and turns only to be slightly disturbed by the ending. I really don't want to give anything away, but I really feel uncomfortable with how one of the female protagonists ends up with her supposed true love and Poirot's condoning it. 

I would have given this four stars if not for that part.