A young boy playing in a field meets an old man who is really an alien collecting specimens to bring back to his planet.

It occurs to Hastings that with fireworks going off all around London on November 5th (Bonfire Night), no one would take much notice of a shooting. And within hours Poirot finds himself investigating a violent death in Hastings's own mews garage. At first, it seems as if a young lady who was about to marry a self-important member of parliament killed herself - but Poirot is not happy with the suicide theory. So if it was murder, who is the killer?