The Fireflash, on its maiden flight from London to Tokyo, is sabotaged by the Hood, a criminal who has learned of the formation of International Rescue, and is unable to land. The Hood's attack is intended to draw out International Rescue so he can record secrets of its machinery for sale to the highest bidder, an attempt thwarted by the intervention of the organization's London Agent.

While returning from a mission, Thunderbird 2 is seriously damaged when it comes under attack from a new, high-speed U.S. Navy strike vessel, the U.S.N. Sentinel. After an operation to move the Empire State Building disastrously ends in the tower's complete collapse, Jeff asks that Thunderbird 4 be transported onboard the same ship to the mouth of an underground river to reach a reporter and his cameraman who are trapped beneath the wreckage.

Lady Penelope goes on the trail of a kidnapped scientist, only to find herself in mortal danger at the hands of a megalomaniac determined to exploit the expert's work to his advantage.

When a new growth hormone is accidentally released into a South American river, a house is besieged by alligators – now many times their normal size. International Rescue must subdue the reptiles and save the house's occupants.

While returning to base, Scott is attacked by mysterious fighter aircraft and shot down over the Sahara. He is discovered by two archaeologists, who send him on his way, only to find themselves entombed within the lost Pyramid of Khamandides.

The Sun Probe rocket and its crew are locked in a collision course with the Sun, prompting the launching of Thunderbird 3 – but International Rescue itself requires saving when Thunderbird 3 is unable to escape the Sun's gravitational pull.

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

During the installation of a new, airtight security vault at the Bank of England, one of the employees is accidentally locked inside, and International Rescue must come to his rescue before the air is extracted.

A criminal organisation steals classified plans. Working in conjunction with a British Secret Service agent, Lady Penelope must recover the material to save the world from total destruction.

World Navy tests of a nuclear torpedo inadvertently threaten the offshore rig Seascape. Jeff, having been invited by Lady Penelope to join her on holiday in Australia, places Scott in charge of International Rescue, with Alan substituting for Scott at the helm of Thunderbird 1. Jeff though is angered when Scott launches a rescue effort to the mid-ocean rig.

A series of unexplained Fireflash airliner disappearances sees Thunderbird 4 being called to rescue a crew stranded on the ocean floor. International Rescue then volunteer its services in helping to diagnose the cause of the mechanical fault.

An unscrupulous investor attempts to recruit Lady Penelope into funding his automated, cross-country monorail building project. Jeff volunteers to ride the prototype, but he, Brains, and Tin-Tin find themselves trapped onboard, and with no possibility of escape, when it is discovered that the monorail train is speeding towards a stricken bridge.

When aircraft are shot down during live broadcasts of a hit song, International Rescue suspects foul play. Tin-Tin and Lady Penelope (posing as the singer Wanda Lamour) investigate, but are left in mortal danger when a ski lift is sabotaged and speeds out of control down a mammoth mountain slide in the Alps.

The Allington Bridge collapses while a space rocket is being transported over it, trapping the rocket on the riverbed and inadvertently initiating its automatic countdown. International Rescue is called upon to save the crew before the rocket launches.

The Erdman Gang has developed an ingenious technique of having their work carried out – an explosive bracelet that can be removed only at the designated target. A secret agent's attempt to infiltrate the organisation backfires as he is left trapped in a plutonium store. International Rescue face a race against time to prevent a massive nuclear explosion.

International Rescue's security is jeopardised when Tin-Tin's close friend Eddie Houseman, who recently visited Tracy Island, takes drastic action to save his road-construction company's threatened contract by planting explosives to tear open a jungle mountainside, and the ensuing chaos leaves him trapped on a cliffside in a truck with another case of explosives on board.

A gang of criminals masquerade as International Rescue to conceal their theft of top-secret military plans. The ensuing worldwide manhunt for International Rescue leaves the organisation powerless to operate in a rescue situation until its name is vindicated, just as a member of a manned reconnaissance satellite is suddenly trapped in space while trying to repair the station.

The Hood sabotages the Red Arrow aircraft programme. One of the planes crashes into the TV Tower in England during a brutal rain storm, and International Rescue is summoned to save the engineers inside the tower before it collapses; making their job trickier apart from the driving rain and winds at the site is that the Red Arrow's director, a long time friend of Jeff, is fired from the project and stays at Tracy Island, forcing the Tracys to draw him away and thus remain oblivious to International Rescue's existence.

The world's tallest tower catches fire following an explosion in the car park and International Rescue are called to rescue a family trapped in the basement, which they can accomplish only with an experimental cutting gas ("Oxyhydnite") that previously rendered Scott and Virgil Tracy unconscious during testing.

After Alan Tracy returns to motor-racing, his rivals decide to remove the competition by rigging a bridge with a movement-sensitive bomb, which will explode the moment that Alan and Grandma Tracy try to escape. (Some of this episode is narrated in flashback.)

The Hood plans to corner the Thunderbirds vehicles by drawing them out to an emergency at an atomic irrigation plant in the Sahara, then photographing them with a miniature camera disguised as a mouse.

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 new invention – the Crablogger (a nearly fully automated logging machine that converts wood into fuel) — threatens widespread devastation if it collides with an unfinished dam, after its drivers collapse due to food poisoning.

A staffed, pirate telecommunications satellite (which broadcasts a music programme of which Tin-Tin is a devoted fan) is disrupted by the detonation of a rogue unmanned space rocket and is set on collision course with a Middle Eastern oil refinery.

Brains and Tin-Tin set off on an expedition to retrieve sunken treasure from Lake Anasta. The Hood has also set his sights on the riches and plans to put both Brains and Tin-Tin in grave peril.