It came to Earth very quietly one evening from an alien planet. It was a mind, a free mind separated from any brain. A galactic mind that had taken one million years of superscience to create.

Dr. Thule Hillory of Serendipity Labs was the only Earthman able to feel the alien presence. Through his PSI experiments, he had already discovered the phenomenon of Psychokinesis.

But now time was running out, and Hillory must work night and day if there's to be any chance to halt the invisible menace!