A mysterious airship orbits through the foggy skies above Victorian London. Its terrible secrets are sought by many, including: the Royal Society; a fraudulent evangelist; a fiendish vivisectionist; an evil millionaire; and an assorted group led by the scientist and explorer, Professor Langdon St. Ives. Can St. Ives keep the alien homunculus out of the claws of the villainous Ignacio Narbondo?