After an asteroid draws an astronaut and his ship to its surface, he is miniaturized by the phantom planet's exotic atmosphere.

Ex-lumberjack Brad Collins (Dennis Morgan) and mining engineer Grady Mathews (William Talman) find uranium in the Colorado badlands. While Grady guards the claim, Brad goes to register it in town, where he meets and marries Jean Williams (Patricia Medina.) Returning to the claim, Brad learns that Jean was once Grady's fiancee. Grady, as one would expect, is somewhat put out and leaves the mine in Brad's hands, while he hooks up with a confidence man and engineers a scheme to break the back of Brad's somewhat rapidly-created mining empire.