 An evil genius of unknown identity, calling himself "Dr. Vulcan" (heard only as a voice and seen as a mysterious shadow on a brightly lit wall), plots to conquer the world.He needs to first eliminate, one by one, the members of the Science Associates, an organization of America's greatest scientists.After narrowly escaping an attempt on his life by Vulcan, one member of Science Associates, Dr. Millard (James Craven) goes into hiding.