Mrs Elspeth McGillicuddy is on her way from a shopping expedition to visit her old friend Jane Marple for Christmas. Her train passes another train running parallel and in the same direction as her train. Then, a blind in one compartment flies up and she sees a man with his back to her strangling a woman. She reports it to a sceptical ticket collector who passes the report for investigation. When arriving at Miss Marple's cottage, she tells all to her. Mrs McGillicuddy describes the dying woman as having blonde hair and wearing a fur coat and the man as tall and dark, though she saw only his back. Miss Marple believes her story, knowing her friend to be trustworthy in description. With no report of a body found in the next day's news, Miss Marple sets out to determine where the body is. With a good map and several rides on the trains to feel the effect of a sharp curve on standing passengers, she determines that the body is on the grounds of Rutherford Hall. Miss Marple sends Lucy Eyelesbarrow, a young professional cook and housekeeper, to work at Rutherford Hall and find the body.