A series of unexplained happenings occur across the eastern United States, caused by objects moving with such great speed that they are nearly invisible. The first-person narrator John Strock, 'Head inspector in the federal police department' in Washington, DC, travels to the Blue Ridge Mountains of North Carolina to investigate and discovers that all the phenomena are being caused by Robur, a brilliant inventor who had previously appeared in Verne's Robur the Conqueror.
