In the book, Poirot is a passenger on board a flight from Paris to Croydon. Some time before landing, one of the passengers, Madame Giselle — a wealthy French moneylender — is found dead. Initially, a reaction to a wasp sting is postulated, but Poirot spies the true cause of death: a poison-tipped dart, apparently fired from a blowgun. It becomes apparent that the victim has been murdered.