My favorite part of this episode was the connection to radio, which was not in the original story. The story itself is routine; a man is found murdered at a large costume party, and the woman who is initially suspected is found dead herself a short time later. One senses that somebody is going to have disguised themselves as someone else, etc. But, from the first words Poirot speaks in the opening scene, I said to myself, "Wait, Poirot is narrating his own story? He's never done that before." I enjoyed the various references to radio plays throughout the episode, and especially liked the very last scene. As many times as Christie was criticized for the peculiar way she had Poirot speak English, at least he had a good excuse for not speaking BBC English. Japp, on the other hand...
