The nuclear-powered hypersonic jetliner Fireflash has been sabotaged by the villainous Hood. Trapped aboard are hundreds of passengers - including Tin-Tin Kyrano, a member of a new organisation, International Rescue. With just hours before their radiation shields fail and the passengers and crew die of radiation poisoning, the fledgling organisation must race to London Airport in their Thunderbirds and find some way of bringing Fireflash down without detonating the bomb.
Unbeknownst to International Rescue, the Hood planted the bomb with the intention of drawing them out, so that he could take pictures of the Thunderbird craft. While he succeeds in taking the pictures, International Rescue's London agent, Lady Penelope Creighton-Ward and her chauffeur Parker are able to intercept and destroy his film and his car with their heavily-armed and bright pink Rolls-Royce.
- Atom Punk: Fireflash is an odd example of this. The dangers of nuclear power on a plane are recognised, but everyone seems to consider it an acceptable risk under normal circumstances.
- Battle Butler: Parker guns down the Hood from the driver's seat of FAB 1
- Cool Car: FAB 1 makes its first appearance
- Early-Installment Weirdness: Extremely mild, but it's there. The arrangement to the Theme Song is slightly different, there are sound effects played during the preview which wasn't done again later, The Hood's clothes are different, and so is Alan's voice (he has one line). More noticably, this is one of the episodes that was stretched from 20 to 40 minutes, and, with the botched initial rescue attempts and the abundance of stock footage, it's extremely noticable.
- Glowing Eyes of Doom: The Hood uses these to signal the activation of his psionic powers.
- Hollywood Skydiving: When Lieutenant Meddings falls out of the Fireflash at less than 6,000 feet, he has time to activate his reserve parachute and land without harm.
- Incredibly Obvious Bomb: Somewhat justified since the bomb was meant to be out of sight, buried in the wing, but still sufficiently obvious to be instantly detectable by the tower's x-ray camera.
- Million-to-One Chance: That's the odds everyone describes an officer's daring plan to board the Fireflash in midair to remove the bomb. As such, no one is particularly confident in it, and it doesn't work.
- Mission Control: Scott takes on this role from the airport control tower, relaying information to Virgil on the runway.
- The Mole: The first example of the unwilling Kyrano filling this position.
- Stuff Blowing Up: The previously mentioned elevator car going out of control, the parked airliner which it crashes into, of course, instantly bursts into flame.
- Theme Tune Cameo: Turns up right at the end.
- Throw It In: During filming one of the Elavator Car models went out of control, however the production team decided to included this in the episode (adding an extra bit of footage of it crashing into some parked aircraft)
- X-Ray Vision: London Tower has a huge x-ray camera, apparently for confirming bomb threats. It's sufficiently advanced to get a nice, big, high-resolution shot even though the aircraft is thundering past at hundreds of miles per hour.