Set in the 1980's, this is Anderson's first series with all live actors. People for years have been disappearing around the sites of UFO landing sites. Some bodies later discovered with organs missing, the governments of the world unite in secret and form SHADO, Secret Headquarters Alien Defense Organization, to combat the apparent alien invasion and try to keep the public from learning about the aliens and panicing. Using a film studio as a cover, Cdr.Straker (Ed Bishop, voice of Capt.Blue from "Captain Scarlet") commands SHADO and its various vehicles and complexes. Vehicles included:

Skydiver-a submarine whose nose cone is actually a supersonic jet fighter capable of being launched from underwater.

Mobiles-heavily armored but small and portable tanks.

Moonbase-first line of defense set on the moon, it houses 3 interceptors, short range fighters with missiles attached to its nose.

Some of the inside jokes in this series are that Cdr.Straker's hair is not really blonde. He only wore a wig as a joke since his earlier character, Capt.Blue, was blonde but Anderson liked the way it looked. Also all the exterior shots of Harlington-Straker Studios, the cover for SHADO, are actually ITC's executive offices.