The Sky Walker seems to be a man walking in the air over Chicago, pushing a barrel-sized object.
His appearance is associated with shattering glass, vanishing railroad tracks that cause a train to derail, the collapse of an office building and a pavilion.
The Gants invented a means of making a glassite airplane truly invisible (except for the engine) and a vibration mechanism that can reduce a target substances to hydrogen.
The criminals use the plane and vibrator to cause the public to lose trust in any steel not made from ore taken from the Catawbi Range, controlled by the gang.
Benson disguises himself as a gang member, interferes with the plane's invisibility treatment, and frees himself and his aides from a death trap.