In the heat of a Central American summer, Miss Withers investigates murder on the Mexico Express.

Oscar Piper doesn't belong on Mexican trains. A New York City detective, he's in the Dominican Republic as part of an international delegation come to cut the ribbon on a new transcontinental highway. This grants him the honor of a trip to Mexico City on the hottest, dustiest train in North America — a crowded slow coach that's about to become a crime scene. The alderman's wife does not know how the bottle of Elixir d'Amour got into her bag. She only knows that when the porter smelled it, he dropped dead. She seems to have been the intended target for the poisoned perfume — but who would want to kill a corrupt politician's trophy wife? Oscar sends a wire to his friend Hildegarde Withers, a schoolteacher and amateur sleuth, whom he knows will not wilt in the Mexican heat. Before she begins her investigation, she has only one question: '¿Cómo se dice 'murder'?' The Puzzle of the Blue Banderilla is part of the Hildegarde Withers Mysteries series, which also includes The Penguin Pool Murder and Murder on the Blackboard.