What new menace was besieging mankind's last refuge?
The Earth had been stripped bare of the atmosphere and water, its surface left an airless and lifeless desert...except for America. A dome of energy had been erected around the U.S. in the nick of time and only within this vast transparent dome could men and women live in safety. Until the moment Barry Thane spotted a moving thing outside the dome!
Something was there where only Death reigned. Something that was spying on the dome, trying to break in and destroy Earth's last oasis! But what was it...and why?

Barry's single-handed struggle with the unknown, his own break-out into the outside world of airless terror, makes one of the most exciting novels that Jack Williamson, master of science fiction, has ever written.