The cleverest man on Earth, Jonas Glebe, becomes the unwitting tool of a baleful intelligence. His invention, the G-Bomb, should bring riches to himself and his daughter Margaret - instead it brings death and a deadly threat to mankind...Val Turner knows the danger, but he's imprisoned - framed for Margaret's murder. His release comes too late to prevent the cataclysm engulfing the world. But fate decrees that he saves a strange little man from drowning, and thereby changes destiny...