Just days after the United States decimated Hiroshima and Nagasaki with nuclear bombs, the Japanese surrendered unconditionally. But even before the surrender, the U.S. government and military had begun a secret propaganda and information suppression campaign to hide the devastating nature of these experimental weapons. The cover-up intensified as Occupation forces closed the atomic cities to Allied reporters, preventing leaks about the horrific long-term effects of radiation that would kill thousands during the months after the blast. For nearly a year the cover-up worked --- until New Yorker journalist John Hersey got into Hiroshima and managed to report the truth to the world.