The luxury airship "Workers' Voyage" is the next target of those capitalist pigs, the Fortune Hunters! They seek to rescue their fellow imperialist, Dr. Wilhelm Fassenbiender, a scientist known for his cooperation with the German fascists and the American capitalists! ...To be honest, Dr. Fassenbiender is an old acquaintance of Nathan Zachary who is abducted by Russian spies to work for them on revolutionary aviation projects. He managed to transmit a distress call to Zachary who is about to improvise yet again with a risky plan to pick the Doctor off the getaway Zeppelin. Surprises besides strong Russian resistance are also expected by other pirate groups, since the luxury Zeppelin is said to bear treasures...