India, Oct. 16 -- In the autumn of 1943, Paris was a city of shadows. The Gestapo prowled the streets with torches, looking for guilty eyes. In the darkness, a young woman's silhouette streaked across with a transmitter, in search of a secret hideout to send a secret message to Britain. And no, this is not just a scene from a Hollywood movie. It was the life of Noor Inayat Khan, the daughter of an Indian Sufi musician and World War 2's most unlikely hero, played by Radhika Apte in A Call to Spy.

I snapped back to reality as I stared at the clandestine Mark II radio at the International Spy Museum (spymuseum.org) in Washington, DC. The transmitter would have been close to 15 kgs at least, and looking at Noor's gentle portrait smiling down...