A nuclear physicist has the duty of sending up atomic bombs in the stratosphere. A photograph indicates an excess of hovering bombs; apparently other countries have been launching bombs too and there is danger of a collision in space. Suddenly, San Francisco has been destroyed. The Secretary of War jumps to the conclusion that Russia did it, so he pulls a switch and destroys Moscow. The race is on. Cities are systematically demolished. Sacramento calls, saying San Francisco was wiped out by an earthquake. But it is too late.