Death in the Clouds (Part 2): "Madame Giselle Paris": Poirot, Mabel, Hasting and the Inspector Sharpe return to Paris. During the flight Poirot studied the positions of the occupants and their movements during the flight killer. In Paris they discover that someone arranged for Madame Giselle was on that flight from Paris. All his fortune will be left to her only daughter was left for adoption for unknown reasons. The Count of Horbury is being blackmailed by his wife who takes money from Madame Giselle to pay his gambling debts.
Death in the Clouds (Part 3): "A Threat to Mrs. Horbury.": All turn out to meet following the "Writer", Mr. Clancy. Poirot asks that Mr. Gale simulate a extortion with Ms. Horbury. Mabel, Poirot and Miss Jane Gray travel again to Paris to unravel the mystery. Mr. Dupont accepts the hint of Poirot to take Miss Jane Gray in his next excavation in Persia. The only daughter of Madame Giselle who inherits an immense fortune appears.
Death in the Clouds (Part 4): "The Heiress of Immense Fortune": After remember that there was already found the daughter of Madame Giselle in flight she was dead, Poirot realizes that she is in great risk of dying, but Mabel he had already left to accompany her to the Grand Hotel and realizes then that she was passing in a taxi with a man going the nearest train station. Inspector Sharpe tries to reach the girl. Poirot gathers all involved to tell what happened on the flight and unravel the mystery.