Aliens, contacting scientist Adam Penner, inform him that they have been on the moon for twenty thousand years, undetected due to their invisibility, and have now decided to annihilate humanity unless all the nations of earth surrender immediately. Sequestered in an impregnable laboratory trying to find the aliens' weakness, Penner, his daughter, a no-nonsense army major and a squeamish scientist are attacked from outside by the aliens, who have occupied the bodies of the recently deceased.
John Agar
Maj. Bruce Jay
Jean Byron
Phyllis Penner
Philip Tonge
Dr. Adam Penner
Robert Hutton
Dr. John Lamont
John Carradine
Dr. Karol Noymann
Hal Torey
The Farmer
Paul Langton
Lt. Gen. Stone
Eden Hartford
WAAF Secretary
