On the evening of June 3, 1934, a strange message was caught by radio fans throughout America. A man calling himself "Serge, Emperor of the Earth," announced that he was about to begin his conquest of the world. He tries to force submission of America by consistently destroying shipping and naval vessels with his radio-directed fleet of one-man submarines.
Two men, Hugh Leigh, a Boston lawyer and secret service operative, and his son Bob, stand between Serge and his ultimate victory--and they have disappeared!