Book excerpt: A gripping true story of wartime espionage. Dundee, 1937. When housewife Mary Curran became suspicious of hairdresser Jessie Jordan's frequent trips to Nazi Germany, she had no idea that she was about to be drawn into an international web of espionage. Thanks to a tip off from Mary, MI5 and the FBI launched major spy hunts on both sides of the Atlantic. This is the true story of a decade-long series of Nazi espionage plots in Britain, Europe and the United States. It shows how a Nazi spy's letter, posted in New York and intercepted in Scotland, broke spy rings across Europe and North America. And it reveals, for the first time, how that letter marked the genesis of an intelligence and security alliance that today includes the United States, the UK, Canada, Australia and New Zealand. 'Fascinating, gripping and expertly researched... an extraordinary true tale of espionage told with all the drama and panache of a spy thriller' – Michael Smith, bestselling author of The Secrets of Station X