[1] The story is set in the far future, where civilization never progresses; the government has determined it to have reached its peak, and to prevent declination, society is forcibly kept in a state of "Stability".
Robert Benton, through the use of his gigantic, detachable white wings, leaps off a roof and flies into the darkness of the night sky.
Activating the device, Benton finds himself transported to an unknown point in history and confronted with what appears to be a living city contained in a glass globe.
Despite being warned not to by a mysterious voice claiming to be a "guardian" against evil, Benton feels compelled to take the globe; it then telepathically informs him how to use the machine to return to his own time.
Benton does so, but travels to a point in time shortly before he originally left, and deposits his "invention" and the plans at the Control office as a patent application, creating a bootstrap paradox.