Thunderbirds Are Go is a British science fiction-adventure motion picture released in 1966. It was the first film based on Gerry and Sylvia Anderson's popular Supermarionation television series Thunderbirds, and followed the first manned mission to Mars.
The new Zero-X, built to be the first manned craft to land on Mars, is prepared for launch. Following an initially successful taxi and take-off, The Hood is on board in disguise taking photographs. Stepping carelessly amongst the hydraulic flight controls, his boot becomes lodged in a vital mechanism causing the pilot to lose control. The Hood, injured and in pain, parachutes from the undercarriage bay, the crew eject safely in their escape capsule, and the Zero-X crashes into the sea before ever leaving the atmosphere.
Following a two-year investigation into the failure of the first mission, during which time a second Zero-X has been built, a commission concludes sabotage. On the eve of the second mission the President of Glenn Field's space control invites International Rescue to provide security for the launch. Jeff Tracy is reticent, as there is no immediate threat to life. Relenting, he allows them to attend, commenting that "rules were made to be broken", sending Scott and Virgil to be on hand at the launch site in Thunderbirds 1 and 2, and calling in International Rescue's London agent Lady Penelope to assist. She foils a second attempt to infiltrate the mission and the take-off proceeds according to plan. Meanwhile, FAB1 gives chase, pursuing the criminal (who proves to be International Rescue's frequent adversary, The Hood) from the airbase, across water at one point, and shoots down his helicopter. Lady Penelope comments that there is no point looking for survivors. (It should be noted that some fans consider this to clearly be the death of The Hood, although—given his penchant for disguises and frequent escapes from supposedly certain death—some have theorised that he is the mysterious villain, the Black Phantom, in the follow-up film, Thunderbird 6.) Zero-X leaves the atmosphere to be escorted briefly by Alan in Thunderbird 3.
After the launch, Scott and Virgil are invited to a nightclub called the "Swinging Star" as Lady Penelope's guests. Back at Tracy Island, Alan feels unappreciated after returning home due to his father's insistence that he remain on duty on the Island while the others are enjoying themselves. Disappointed and annoyed, Alan has a dream about going with Lady Penelope to the Swinging Star, which in his dream is located in outer space. Playing at the nightclub are "Cliff Richard Jr. and the Shadows" (puppets and voices of the real Cliff Richard and the Shadows), who perform a musical number called "Shooting Star" (accompanied by music video-like imagery such as the Cliff Richard Jr. marionette dancing on a giant guitar in space), and an instrumental track "Lady Penelope". Alan's dream sequence ends abruptly when he falls back down to Earth, and wakes up to discover he has fallen out of bed.
The Zero-X has landed on Mars, and is exploring the Martian surface, which is a desolate landscape of rock. The crew are particularly intrigued by unusual rock formations, large stone coils, which they decide to shoot to collect samples to take back to Earth. However, these formations are actually living creatures, one-eyed rock snakes, which do not seem to be able to move their main bodies and once provoked they begin shooting fire-balls at them, forcing the crew to make a swift departure without making as detailed assessment as they would have liked.
On re-entry to Earth's atmosphere, Zero-X's second lift body malfunctions and fails to connect properly with the main body, causing damage to the craft, including to the controls for the crew escape pod. International Rescue is called to assist, and Alan has to risk being trapped on board the doomed vehicle as Brains instructs him how to bypass the broken circuit. Alan is left with mere seconds to escape on his safety line, and the crew are evacuated in the nick of time, before the final spectacular impact on the evacuated town of Craigsville.
Afterwards, Alan is having what he thinks is a quiet tête-a-tête with Lady Penelope at the real Swinging Star, only to find that he is surrounded by the whole Tracy family in disguise, including Brains without his ever-present spectacles—and to his great embarrassment— Tin-Tin. Nevertheless, they all heartily drink a toast to Alan as the "hero of the day".
The end credits feature the Band of the Royal Marines playing Barry Gray's Thunderbirds March, eventually forming "The End" on the parade square. Other than the voice credits, the names listed are organisations or characters from the film.
Thunderbirds are Go functions as a link between the 1964–1966 television series Thunderbirds and the 1967 series Captain Scarlet and the Mysterons. The Zero-X craft appears in both. The plot point of peaceful creatures on Mars that suddenly turn hostile to humans when provoked also begins Captain Scarlet and the Mysterons, although the "rock snakes" do not appear in the later series.
The size of the solenoid operating the puppet mouths (dubbed Supermarionation) had been the main factor dictating the need for oversized caricatured heads. This film was the last to make exclusive use of the disproportionately large heads. Advances in technology meant the solenoid could be moved into the body cavity and hence the marionettes' heads could be scaled to correct human proportions for Captain Scarlet and the Mysterons and later series.