Parker Pyne is still in the orient on his way to Teheran, then Shiraz. He is taking the route by a monoplane flown on the first leg on the journey by a young German pilot called Herr Schlagal. Disappointed with the modernity of Teheran, Pyne invites Schlagal to dine with him and they talk of his job flying across the Middle East. The pilot tells of his first two passengers, a young titled lady called Esther Carr and her beautiful companion who Schlagal fell in love with. Soon after, the second young woman was dead and Schlagal suspects Lady Esther of the murder, seeing insanity in her eyes and in her manner. Pyne knows of Lady Esther's parents and of her family where insanity has been a curse through some of the generations down the years.