The Invisible Empire

• First published 1936

The Invisible Empire is a group of terrorists that attempted to assassinate the president, invade Washington, D.C., and pillage the United States Treasury and Experimental Science Building. Later, the group destroyed a metropolitan bridge and unleashed a stories-tall robot, which carved a destructive path through the city. The group used military machines and weaponry, planes, zeppelins, and high-tech equipment including ray-guns and towering robots in their attacks. Their numerous plans were thwarted by the Federal Men and significant action by agent Steve Carson.