Jo Hardy, a 22-year-old ferry pilot, is delivering a Supermarine Spitfire --- the fastest fighter aircraft in the world --- to Biggin Hill Aerodrome, when she realizes someone is shooting at her aircraft from the ground. Returning to the location on foot, she finds an American serviceman in a barn, bound and gagged. She rescues the man, who is handed over to the American military police; it quickly emerges that he is considered a suspect in the disappearance of a fellow soldier who is missing. Tragedy strikes two days later, when another ferry pilot crashes in the same area where Jo’s plane was attacked. At the suggestion of one of her colleagues, Jo seeks the help of psychologist and investigator Maisie Dobbs.