The doughty Sir Denis Nayland Smith hot on the trail of his ancient adversary, Fu Manchu, as he, and America, Russia, England race to get the secret of a potential that will neutralize atomic war which young scientist Morris Craig has discovered. Chase and counter-chase mark Smith's hounding of the Asiatic insane genius, now out to save the world from the ""leprosy of Communism"", and the desperate battle- in a production of disguises, Oriental fast plays,- climaxes with the discovery of the Soviet agent and the honesty of Craig. Thriller with all trimmings- and a Crime Club selection.