With the moon's trajectory reported to be shifting due to an unknown cause, the Alphans happen across a roving spaceship run entirely by a computer. Brian the Brain, as he prefers to be called, proves to be a devious device until the truth is uncovered.

Titan orders Agent X-20 to kidnap a pop star who is visiting Marineville.

A blackmailed SHADO operative opens the door for a possible alien attack on Moonbase.

Following a recommendation in a brochure, the Paradox crew decide to take a holiday on the planet Brightonia on Sea. But once there, they are captured by Short Fred Ledd who chains them up and steals the Paradox. Without water, their only hope of survival rests with Sir Squeakalot and Isambard’s latest invention, a remote control for the Paradox.

Mike and Dr. Beaker try to find a forger's plates - if an art dealer and a criminal don't find the plates first.

Yung-Star runs away, but he is unknowingly carrying a 'bug' in the form of a powder inside him.

A wealthy man is concerned to discover his teenage daughter is involved with an obscure religious sect. Harry goes undercover to find out what goes on inside the community.

Jonathan Zero's unauthorised midnight exploration of XL5 turns into a terrifying adventure when the ship launches and catches fire.

The resident toys are no longer amused with Pilliwig's jokes, which depresses the clown. Torchy and Flopsy decide to picnic on an island, where they discover Ena the hyena. They bring her back to Frutown, where Pilliwig is delighted to meet someone who will always laugh at his antics.

Pteronarcys Eternicum, a rare beetle capable of cell regeneration, is stolen from Dexkor Laboratories. Brogan and Haldane are assigned to the case and suspect that the theft may be an inside job. But Brogan is preoccupied with nailing drugs dealer Amory Wolf whom he believes is responsible for the death of Tommy Murphy, his oldest friend. Meanwhile, Jane and Took have a run-in with local hero Thunder Cole.

Joe attempts to thwart Mario Coletti, a ruthless arms runner who sells weapons to the highest bidders.

While investigating the destruction of an oil platform with Troy and Phones, Atlanta is captured by undersea warriors.

After Captain Black inadvertently exposes himself to radiation, thus making himself detectable on long-range Geiger counters, Spectrum mobilises its forces to apprehend the Mysterons' primary agent.

Pedro and Fernando set a fire on the outskirts of town to lure Tex away. The bandits aim to rob the bank while Tex and the other townsfolk fight the fire.

Approaching an inhabited planet, the Alphans are suddenly pounced upon by warships. In an unprovoked attack, Moonbase Alpha is devastated by Earth-style Hawk fighters. With 128 dead and Alpha unable to sustain life, Koenig and Helena appeal to the aliens for mercy. The aliens proclaim the Earthmen to be an invading virus, with no right to exist.

In a remote diner in Phoenix, Arizona, Spectrum flight engineer Xander Story makes contact with two Mysteron agents. Story agrees to destroy Spectrum's Skybase in return for the aliens' promise that they will halt their war on mankind – he accepts a fusion bomb in a briefcase and also a large payment. Captain Scarlet gatecrashes the meeting but is shot and killed. Knowing that his body will regenerate, the Mysterons try to engineer Scarlet's total destruction in a massive explosion. Captain...

When the Ocean Pioneer tanker inexplicably explodes, Brains investigates the cause. With some help from Lady Penelope, he discovers it to be a chemical reaction between the cargo of liquid alsterene and OD60, which is found in the sea. International Rescue set out to save the crew of the ill-fated Ocean Pioneer II.

A film director hires the Protectors to investigate when copies of his latest film are stolen and a ransom is demanded.

Unwin and Matthew investigate what appears to be a case of sabotage when the AquaTank, a new military robot of the World Army, develops a mechanical fault. As NATO officials attend a demonstration of the AquaTank's capabilities, suspicion falls on Captain Mitchell when he instructs computer expert Professor Graham to program the tank to fire on the officials' bunker.

Fernando and Pedro try to get arrested so they can spend the night in jail. The pair wants to dig underneath the jailhouse and on into the bank to rob it.

A SHADO pilot believed dead suddenly turns up alive – much to a SHADO operative's suspicion.

When Surface Agent X-2-Zero frames a navy captain for a sabotaged torpedo test, it is up to Troy to clear the man's name.

By a trillion to one chance, the Paradox discovers Roger’s old Starfighter, the Firefly, adrift in space. Isambard goes aboard to effect repairs, but it is the inexperienced Sproggle who ends up in the cockpit of the Starfighter when Dr. Agon’s Mammoth Machine closes in on the Paradox!

Zelda dispatches Yung-star and a new monster, Lord Tempo, to find the location of Hawknest. While traveling back in time to avoid Spacehawk, they pick up King Richard III.