The bombing of Japan, the Soviet's "First Lightning" test, and America's H-bomb detonations were powerful signs that the Nuclear Age was upon us. But as recently declassified files reveal, explosive events were also carried out in secret. Discover how far the U.S. government went to protect its Cold War intel and how close the world came to total annihilation. From the framing of Ethel Rosenberg to radiation experiments on unsuspecting civilians, this is a grim look at the quieter side of the Atomic Age.