Col. Pete Moore (Glenn Ford) heads a radar testing squad for the Air Force. When two fighter jets disappear under his command while in pursuit of what he believes was a U.F.O., the monitoring plane is made to land by a mysterious government agency known only as Digger Control, supposedly aiming to explain or discredit U.F.O. sightings. Moore, unaware of Digger Control's grounding of the plane, disobeys orders and mounts his own investigation to find the truth about his men.