On the evening of May 16, 1937, the train doors opened at the Porte Doree station in the Paris Metro to reveal a dying woman slumped by a window, a nine-inch stiletto buried to its hilt in her neck. No one witnessed the crime, and the killer left behind little forensic evidence. The murder in the Paris Metro dominated the headlines for weeks, as journalists and the police slowly uncovered the shocking truth about the victim: a twenty-nine-year-old Italian immigrant and spy, the beautiful Laetitia Toureaux.