August 29th, 1949: four years after the U.S. drops the first atomic bomb, the Soviets drop one. No one expected it so soon. Behind the scenes of this major event of the cold war, the Soviets developed one of the biggest networks of moles of the century. In this episode of “Spies of War”, you will discover how and why brilliant scientists divulged the secrets of the atomic bomb to the sworn enemy of the U.S, and how U.S. counter-intelligence services cracked their codes to expose the leaks.