Around 1970, the British and American governments receive incontrovertible evidence that aliens exist and are abducting humans. In cooperation with the United Nations, they set up a secret worldwide organization, SHADO (Supreme Headquarters Alien Defence Organisation), which operates in the 1980s. With resources and equipment under the seas, in the air, on land, in orbit and on the Moon, SHADO's purpose is to stop the alien incursions and find out why the aliens want humans.
SHADO is based in England, with headquarters beneath Harlington-Straker Studios, a working motion picture studio constructed purely as a cover for SHADO. Its uppermost echelon was made up of a commander and colonels.
Commander Ed Straker - SHADO's commander in chief, involved in the UFO program even before SHADO was formed. Formerly a USAF colonel, he sacrificed ten years of his life to get SHADO up and running. His cover is as chief executive of Harlington-Straker Studios.
Colonel Alec Freeman - A friend of Straker from military service. When SHADO was first approved, Freeman became its first recruit on Straker's recommendation.
Colonel Paul Foster - A test pilot who was nearly killed in a UFO incident, Foster impressed Straker with his resourcefulness, tenacity and unwillingness to accept anything but the truth.
Colonel Virginia Lake - A brilliant systems designer and technician, the beautiful Colonel Lake took the place of Colonel Freeman in the second half of the season.
The series was actually filmed in two blocks of episodes months apart because the original studio it was filmed at closed down. By the time production restarted, some of the cast was no longer available. Others had left soon after the series began either to avoid typecasting or because of dissatisfaction with very short-term contracts.moreless