
A secret, high-technology international agency called SHADO defends Earth from alien invaders.

SHADO engages in its first battle with the enemy. Sky One cripples an alien ship which crash-lands in a lake. Straker's team capture its pilot, a strange blue-skinned humanoid - and the grim secrets behind the alien motives are revealed.

An XV-104 test plane wanders into a UFO target area and the pilot, Paul Foster, makes sightings of both the UFO and Sky One. Angry and frustrated that no one believes his story, Foster suspects a cover-up and decides to conduct his own investigation into the activities of ex-USAF Colonel Ed Straker.

The body of an Alien, recovered after a UFO attack on Moonbase, reveals some startling new evidence which overturns all SHADO's previous theories about the Aliens. For Interceptor pilot Jim Regan, the news has tragic consequences as he becomes possessed by the mind of an Alien held in the body of a Siamese cat!

When an Alien Limpet UFO causes the destruction of Lunar Module 32, Straker demands a clean-up programme by the International Astrophysical Commission to remove hazardous space debris from Earth orbit. But Straker finds himself butting heads with I.A.C. chairman James Henderson, who wants a complete shut-down of SHADO operations...

"Important? What can be more important than your own son's life?" Straker faces the toughest decision of his career when his son is critically injured in an accident. The drug that can save his life can only be ferried from New York in time aboard a SHADO Transporter - the same Transporter that is in the prime position to track an Alien defector on the West Coast of Ireland.

John Croxley's talent for extra sensory perception is heightened after his wife is killed when a UFO crashes into their house. With his mind under the influence of the Aliens, Croxley learns the secrets of SHADO and lures Straker and Freeman to the remains of his house - to kill them!

When a Lunar Module is attacked by a UFO, Straker makes a split-second decision that endangers the astronauts, but ultimately saves them. Later, he is surprised to find his authority being questioned by his most loyal officer, Colonel Paul Foster, who spearheads a campaign against him. Then an attempt is made on Straker's life...

Suspecting a UFO to be responsible for the sinking of a freighter, Straker, Foster and Nina Barry investigate in Skydiver. Attacked by an undersea UFO, the submarine is downed on a ledge on the sea bed and the crew are trapped. While Straker fights against his claustrophobia, Nina faces a living nightmare...

A Naval vessel shoots down a UFO in the Atlantic, but the Admiralty rejects further investigation into the incident. Straker suspects a cover up and wants to know why, so Foster courts Admiral Sheringham's secretary, Sarah Bosanquet. What they discover could mean the end of all life on Earth...

"Unfortunately for them, an Alien came through that door instead of her husband." In the woods between Clare Cross and Lingbury, an injured Alien stumbles into a lonely cottage and is shot down by Liz Newton and her lover Cass Fowler. Liz and Cass are taken to SHADO HQ for questioning, but when Liz's husband arrives at the cottage, Paul Foster realises that the Alien's death was no accident!
Created by: Gerry Anderson, Sylvia Anderson
Available on: Associated Television