Two Hungarian-Jewish scientist, Leo Szilard and Edward Teller, flee to America after the Nazis take control of Germany, and convice the US government to launch its own atomic project in an effort to prevail over the Germans.

With Germany losing the war andrealizing the potential destructive capabilities of the atomic bomb, the scientists attempt to halt its development xhixh no longer seems vital. The US government opposes their views. Research continues and the first bomb is tested in the Nevada desert.

When the bomb is dropped over Hiroshima, Leo Szilard continues his anti-nuclear campaign while Edward Telle resumes his research, believing he can end war forever. After learning that Russians have developed a transportable H-Bomb first, the FBI initiates an investigation of the Atomic Energy Commission.