Every family has its secrets. Director Peter Stephan Jungk had always known that his Austrian-born great aunt, Edith Tudor-Hart, was a talented documentary photographer. But it was not until 20 years after her death in 1973 that he learned she had led a double life — and changed the course of history.

Jungk unravels what had been a well-kept secret by speaking with military historians, photo archivists, ex-KGB agents and family members: that his great aunt, an unpaid KGB spy, had brokered the introduction between Kim Philby and Soviet spy Arnold Deutsch, thereby helping launch the espionage career of Britain’s most notorious double agent, who was the lynchpin of the Cambridge Five spy ring.

Through these conversations and the striking photographs of Tudor-Hart herself, Jungk takes us on a journey into his great aunt's clandestine life that is as gripping as a spy novel.