Thunderbird 6

In 2068, the New World Aircraft Corporation in England issues Brains an open brief to design a revolutionary aircraft. Brains suggests an airship, prompting laughter from the executives. Nevertheless, the proposal is accepted and Skyship One is built for the maiden voyage.

Jeff asks Brains to design a sixth Thunderbird machine. Brains works without a formal specification, producing a range of concepts that Jeff rejects. Brains remains on Tracy Island while the Skyship One project goes ahead.

Alan and Tin-Tin fly to England in Alan's restored Tiger Moth, meeting Lady Penelope and Parker. The four then board Skyship One for its maiden voyage, prepared to undertake a round-the-world trip. The team represents International Rescue for the flight.

As Skyship One departs, Captain Foster and the ship's stewards are murdered and replaced by The Hood's agents, operating as Black Phantom from an abandoned airfield near Casablanca. The impostors blend in with the automated crew, avoiding suspicion. The guests remain unaware of the looming threat.

Penelope discovers a bugging device in her bedroom, revealing The Hood's plan to edit and broadcast a fake radio message luring Thunderbirds 1 and 2 to the airfield. Parker finds the editing equipment. The message is sent to Tracy Island via Thunderbird 5, setting the trap into motion.

Jeff immediately orders Thunderbirds 1 and 2 to respond to the emergency. Alan realises the flight is a trap and warns Penelope, who manages to relay the warning in time. The team braces for interception while the impostors stay hidden aboard Skyship One.

Scott and Virgil arrive in Thunderbird 1 and 2 and land at the abandoned airfield. They unleash rocket launchers to destroy The Hood's base and its operatives, preventing the capture of the guests. They then depart to rendezvous with Skyship One.

Back aboard Skyship One, a shootout erupts as the impostors resist surrender. Tin-Tin is taken hostage, and the anti-gravity system is damaged, causing the airship to lose altitude and crash into a radio mast at a missile base near Dover. The ship hangs precariously atop the mast as its systems fail.

With the ship grounded, Brains volunteers to airlift the passengers using the Tiger Moth. The attempt puts him at gunpoint by Foster, while Penelope is held hostage in the Tiger Moth's cockpit. Foster tries to escape, but Alan shoots him dead, enabling the rescue operation.

The Tiger Moth, carrying the guests and impostors clinging to wings and landing gear, launches away as Skyship One crashes to the ground. The collision triggers a chain reaction that obliterates the missile base nearby. The guests survive, but the villainous attempt collapses.

The remaining impostors are killed in a gunfight aboard the Tiger Moth. Penelope makes an emergency landing after stray bullets puncture the fuel tank, narrowly avoiding factory chimneys, a motorway bridge, and a tree. Parker is thrown from the plane, ending up dangling in its branches.

Back on Tracy Island, Brains unveils Thunderbird 6 as the Tiger Moth reconditioned for combat. The team agrees that this improvised craft has proven its value in the field, sealing its place in the fleet.