In 2068, the New World Aircraft Corporation in England gives
Brains an open brief to design a revolutionary aircraft. Brains suggests an
airship, prompting howls of laughter from the executives. Nevertheless, his proposal is accepted and the corporation builds
Skyship One, a fully automated craft powered by an
anti-gravity field. Representing International Rescue for the maiden flight – a round-the-world trip with computer-programmed stops – are
Alan Tracy,
Tin-Tin Kyrano,
Lady Penelope and
Parker. Brains is forced to stay on
Tracy Island after
Jeff asks him to design a sixth
Thunderbird machine. Working without a specification, Brains produces a range of concepts but Jeff rejects them all. Alan and Tin-Tin fly to England in Alan's restored
Tiger Moth biplane. They meet up with Penelope and Parker and the four of them board
Skyship One. As the airship departs on its voyage, the group are unaware that Captain Foster and the stewards have been murdered and replaced by agents of the
Hood, now operating as "Black Phantom" from an abandoned airfield near
Casablanca. As the ship is automated, the impostors do not need to demonstrate any technical knowledge and are able to avoid raising their guests' suspicions. After
Skyship One leaves the
Egyptian pyramids, Penelope finds a
bugging device in her bedroom. Foster and his men have been recording and editing her voice to assemble a fake radio message asking Jeff to send
Thunderbirds 1 and
2 to the airfield, where the Hood and his men plan to capture the two craft. Parker uncovers the editing equipment, but before the group can act, the impostors complete the message and transmit it to Tracy Island via
Thunderbird 5. Jeff immediately dispatches
Scott and
Virgil in
Thunderbirds 1 and
2, but Alan realises that his brothers are flying into a trap and Penelope manages to relay the warning just in time. Landing at the airfield, Scott and Virgil use the
Thunderbirds rocket launchers to destroy the Hood's base. They then take off to rendezvous with
Skyship One. Aboard the airship, the guests engage the impostors in a shootout. Tin-Tin is taken hostage, forcing their surrender. During the fighting, the anti-gravity system is damaged, causing the ship to lose altitude and crash into a radio mast at a missile base near
Dover. With
Skyship One balanced precariously on top of the mast and its anti-gravity field weakening, it is up to Scott, Virgil and Brains to rescue everyone on board before the ship collapses onto the base below. Scott and Virgil are unable to approach the airship without tipping it over with their thrusters and there are no
Thunderbird 2s
pod vehicles light enough to deploy onto it. At
Gordon's suggestion, Brains flies the Tiger Moth up to the top deck to airlift the passengers and crew to safety, only to be held at gunpoint by Foster and his surviving henchmen. With Penelope a hostage in the plane's cockpit, Foster tries to take off but is shot dead by Alan. The Tiger Moth launches with the guests and impostors clinging on to the wings and landing gear. Shortly after,
Skyship One finally crashes to the ground, starting a chain reaction that obliterates the missile base. The remaining impostors are killed in a gunfight aboard the Tiger Moth. Stray bullets puncture the fuel tank, forcing Penelope to make an emergency landing. After near misses with a factory chimney, a bridge on the M104 motorway and a tree, Penelope ditches the plane into a field. Parker is thrown out when the plane clips the tree top and ends up dangling in its branches before falling to the ground. Back on Tracy Island, Brains unveils the new
Thunderbird 6 as none other than the repaired Tiger Moth, which all agree has proven its worth in the field. ==Production==