Test space rockets exploding at liftoff and increased reporting of UFO sightings culminate in a direct attempt by alien survivors of a dead, extra-galactic civilization to invade Earth from impervious flying saucers, using ray-weapons of mass destruction.
Hugh Marlowe
as Dr. Russell A. Marvin
Joan Taylor
as Carol Marvin
Donald Curtis
as Maj. Huglin
Morris Ankrum
as Brig. Gen. John Hanley
Thomas Browne Henry
as Vice Adm. Enright
Grandon Rhodes
as Gen. Edmunds
John Zaremba
as Prof. Kanter
Paul Frees
as Alien (voice)
Frank Wilcox
as Alfred Cassidy
Sydney Mason
as Frank the garage man
Larry J. Blake
as Motorcycle cop
Bert Stevens
as Air Intelligence Command Officer
