Three disused freighters mysteriously disappear shortly before they are due to self-destruct.

Intro special guest: James Swallow

A lush Earth-type planet holds the promise of a new home for the people of Moonbase Alpha. When the reconnaissance Eagle returns, it carries an unexpected passenger: Helena's husband, who died five years ago. The mysterious Lee Russell tells the Alphans that death awaits them on the new planet. The Alphans ignore his warning and unknowingly descend into a world of antimatter.

Intro special guest: Paul Shipper

Convict George Gray breaks out of prison and makes contact with Sir Humphrey Burton, who has promised him passage out of Britain aboard a submarine. Unwin is assigned to intercept the pair.

Intro special guest: Paul Shipper

Destiny Angel is kidnapped by Captain Black, and sometime later, it looks as though Destiny has staged a daring robbery of some missile launch codes. It appears that she has turned into a Mysteron agent, but things are not as they appear when Captain Scarlet goes looking for her and finds that her so-called "betrayal" is only the first stage in an attack on Skybase.

Intro special guest: Gary Tomkins

Marvin Jackson is trying to sell the Eureka Silver Mine, but the main buyer, Harman, pays Pedro and Fernando to pretend to be ghosts to bring the price down.

Intro special guest: Gary Tomkins

A SHADO interceptor pilot is placed under a hypnotic spell by an alien-influenced cat.

Intro special guest: Sam Clemens.

The daughter of a gangster returns after his death to kill Harry. Or does she?

The Mysterons threaten to assassinate the Supreme Commander of the Earth Forces.

A 500-ton U.S. Army walker, the Sidewinder, falls into a pit during testing and International Rescue are called to save the crew trapped inside.

A cloud of space dust causes a mystery illness on Alpha; an Eagle crew is sent to discover its secrets, but the craft returns only with a strange beast that withstands all assaults and which Maya realises is not a life form. The senders of the beast want elements of Alpha's life support system.

Intro special guest: Kate Harbour