EPISODE 1: THE MYSTERONS
"Our first act of retaliation will be to assassinate your World President"

Those chilling words are how The Mysterons, a race from Mars declare war on Earth in the year 2068 after they mistakenly believe their Martian city has been attacked by mankind during an exploratory expedition led by Captain Black of The Spectrum organisation, who are co-incidentally Earth's first line of defence.

During The Mysterons attempt to carry out their threat, two Spectrum agents, Captain Scarlet & Captain Brown are killed and duplicated and sent on a suicide mission to assassinate the World President. Scarlet kidnaps the President and is pursued by Captain Blue, Scarlet's best friend, and they engage in a shoot out atop an 800 foot high building. Blue shoots Scarlet who falls to his death, its then that Spectrum make an amazing discovery that will aid them in the forthcoming war of attrition with The Mysterons.

EPISODE 2: WINGED ASSASSIN
"We will assassinate the Director General of the United Asian Republic"

After making a full recovery from his fall where Spectrum discover that Captain Scarlet is able to regenerate himself, Scarlet along with Captain Blue is sent to take part in the operation to protect the Director General of the Asian Republic who is the latest target of The Mysterons.

EPISODE 3: BIG BEN STRIKES AGAIN
"Our next act of retaliation will be to destroy the city of London"

Scarlet is sent to deal with a deadly situation after The Mysterons seal an atomic device in an underground car park 10 miles outside of London.

EPISODE 4: MANHUNT
There is no specific threat made in this episode

Captain Black who by now is a Mysteron agent, attempts unsuccessfully to break into the Culver atomic centre, but during his escape he steals a Spectrum Special Patrol Vehicle (SPV) & takes Symphony Angel hostage.

EPISODE 5: AVALANCHE
"We will destroy key-links in your front line outer space defence system"

The Mysterons threaten the Alaskan chain of missile complexes & Colonel White sends Scarlet & Lieutenant Green to investigate when they lose contact with one of the missile bases.

EPISODE 6: WHITE AS SNOW
"Our next act of retaliation will be to kill the commander in chief of Spectrum, Colonel White"

After The Mysterons threaten his life, Colonel White decides that in order to safeguard the lives of everybody else on Cloudbase, he will leave for a secret destination.

EPISODE 7: THE TRAP
"At the appointed hour, as the clock is chiming, the wings of the world will be clipped"

Spectrum is assigned to provide the security for an international air conference, at which all the high ranking officers of the World Air Force will be attending.

EPISODE 8: OPERATION TIME
"Our next act of retaliation will be to kill time"

General Tiempo, commander of the Western Region World Defence, is to undergo brain surgery. The Mysterons, via Captain Black kill then take over professor Magnus the surgeon who is to supervise the operation.

*In this episode it's discovered that The Mysterons can be killed by high voltage electrical current.

EPISODE 9: SPECTRUM STRIKES BACK
"You will never solve the mystery of The Mysterons"

Colonel White along with Captain Scarlet & Captain Blue travel to the secret H.Q of the Spectrum Intelligence Agency to attend a demonstration of new weaponry with which to fight The Mysterons. Captain Black also attends this meeting but for other reasons.

*This episode was originally intended to be a sequel to the previous episode, Operation Time.

EPISODE 10: SPECIAL ASSIGNMENT
"We intend to obliterate the sub-continent of North America"

Scarlet is forced to resign from Spectrum for breaking strict anti gambling rules and teams up with Captain Black.
Or does he?

EPISODE 11: THE HEART OF NEW YORK
"We've seen the greed & corruption of the world in which you live & will take our revenge upon it"

New York is evacuated & Spectrum sent in after The Mysterons threaten to attack the city, at the same time three bank robbers decide it's the perfect time to rob a bank.

EPISODE 12: LUNARVILLE 7
"We have no quarrel with the Moon & we accept their offer of friendship"

Scarlet, Blue & Lt Green are sent to the Moon to investigate claims by the Lunar controller that he has established contact and negotiated a peaceful agreement with The Mysterons.

This is the 1st of 3 episodes that features Gerry Anderson's voice as the Lunarville computer, SID.

EPISODE 13: POINT 783
"We shall destroy the supreme commander of Earth forces within the next 24 hours."

Captains Scarlet & Blue are sent to deal with The Mysterons' latest threat.

EPISODE 14: MODEL SPY
"We are about to attack the house of Verdain."

The Mysterons threaten the life of a top fashion designer, so Captain's Scarlet & Blue travel to Monte Carlo with Symphony & Destiny Angels where his latest fashion show is being held.

EPISODE 15: SEEK & DESTROY
"We intend to kill one of The Spectrum Angels"

The Angel's are embroiled in a deadly battle to save one of their own.

EPISODE 16: RENEGADE ROCKET
"We are going to launch one of your own incendiary rockets and you will have no way of knowing its target."

Captain Black kills a rocket base commander who is then duplicated on his way to Base Concorde an island based rocket installation, in order to carry out the latest Mysteron threat.

EPISODE 17: CRATER 101
"Although you have discovered our complex on the Moon, it will never reveal its secrets."

Scarlet, Blue & Green return to the moon to investigate the newly discovered Mysteron moon complex.

*This episode is a sequel to Lunarville 7.

EPISODE 18: SHADOW OF FEAR
"You will never discover the secret of The Mysterons"

Captains Scarlet & Blue are sent to an isolated observatory in the Himalayas to observe the landing of a mini satellite on the Martian moon of Phobus.

EPISODE 19: DANGEROUS RENDEZVOUS
"Spectrum Cloud base will be destroyed at midnight"

The Mysterons in response to Colonel White's offer of peace insist that a member of Spectrum meets their representative at a location of their choice.

EPISODE 20: FIRE AT RIG 15
"We intend to immobilise the whole of Spectrum"

The Mysterons cause a fire at a Spectrum oil refinery.

EPISODE 21: TREBLE CROSS
"We will destroy the world capital, Futura City."

Captain Black attempts to kill an ace test pilot, but doesn't realise he's failed, meanwhile the real test pilot joins Spectrum and hatches a daring plan to deceive The Mysterons.

EPISODE 22: FLIGHT 104
"The conference at Lake Toma will be sabotaged."

Captains Scarlet & Blue are assigned to escort a leading astrophysicist to a special conference in Switzerland.

EPISODE 23: PLACE OF ANGELS
"We will destroy the place of the angels"

A laboratory assistant at a bacteriological research centre falls under control of The Mysterons and steals a phial of a newly developed culture that is capable of causing death on a massive scale and heads for the Boulder Dam in order to contaminate the water supply for the city of Los Angeles.

EPISODE 24: NOOSE OF ICE
"We will make sure that you never return to our planet, Mars."

Scarlet faces a battle against time & nature as he tries to avert disaster at a site where scientists are drilling deep below the polar ice cap for a rare metal that is essential for a new space fleet bound for Mars.

EPISODE 25: EXPO 2068
"Disaster will strike the Atlantic seaboard of North America. We will deal a heavy blow to the prestige of the World."

A nuclear reactor disappears during transit & Spectrum suspect The Mysterons.

EPISODE 26: THE LAUNCHING
"We will destroy President Roberts within the next 24 hours."

Colonel White sends Captains Scarlet & Blue to protect The President; while Scarlet is trying to convince him he's in danger a Mysteron agent in the area has his sights on a far bigger target.

EPISODE 27: CODENAME EUROPA
"The triumvirate of Europe will be destroyed."

The three most powerful men on Earth after the President are marked for death by The Mysterons.

EPISODE 28: INFERNO
"Our next act of retaliation will be to destroy the complex at Najama."

Scarlet and Blue set up camp in an old Aztec temple in the foothills of The Andes to keep vigil on a desalination plant that has been threatened by The Mysterons.

EPISODE 29: TRAITOR
"The Spectrum organisation will be torn apart from within."

The Mysterons announce that a traitor will create havoc for Spectrum from within their own ranks.

EPISODE 30: FLIGHT TO ATLANTICA
"We intend to destroy the World Navy complex at Atlantica."

Captains Blue & Ochre under the influence of too much champagne, (which has been doctored by The Mysterons ) and having their flight plan changed by Captain Black , attack the World Navy complex. They are pursued by Colonel White & Scarlet and White is determined to stop them even if it means shooting them out of the sky.

*This episode contains an instrumental version of the song "The dangerous game" which was sung by Lady Penelope in the Thunderbirds episode "The Cham Cham."

EPISODE 31: ATTACK ON CLOUDBASE
"We will destroy Cloudbase"

Symphony Angel is shot down over the desert and The Mysterons launch an all out attack on Cloudbase. It appears at the end of this episode that The Mysterons have won the war.

EPISODE 32: THE INQUISITION
"One of the members of Spectrum will destroy you all."

Captain Blue awakes in a deserted Cloudbase control room and finds a man named Colgan sitting at Colonel White's control desk who informs him that he's from Spectrum intelligence and that Blue has been missing for 3 months. He informs Blue that in order to prove his identity, he has to tell him the Spectrum cipher codes.

*This episode uses mainly flashbacks from previous episodes.