 The chapters of this serial each ended with a brief tutorial in cryptography.This serial introduces the World War II scenario when a masked hero tries to prevent Nazi agents from crippling the US's war effort.The spy ring is led by fifth columnist Jensen, who, with his lieutenant Rudy Thyssen and a network of Nazi saboteurs, is trying to get possession of a top-secret formula the United States had developed for manufacturing synthetic rubber while creating explosive gases and radio-controlled bombs to sabotage the exhausting war effort.