The spacecraft Zero-X is bound for Mars, carrying a crew of five astronauts. But when the craft experiences a critical mechanical fault shortly after take-off, the crew are forced to eject to safety while the multi-million dollar spacecraft crashes into the ocean. Two years later, an investigation committee releases the official report on the crash, concluding that the cause of the crash was sabotage. While the mission is put on hold, the committee decides that extra security measures would be required for a re-launch. After some debate, they decide to call on the services of International Rescue. The Thunderbirds machines, with the help of London Agent, Lady Penelope, make sure that the second launching attempt is successful. Once the craft lands on Mars, the crew start to explore the planet and collect rock samples, but when they encounter unexpected problems, they are forced to return to Earth sooner than planned. On re-entering Earth’s atmosphere, the crew encounter further problems when a lifting body (one of two remote controlled wings equipped with additional engines and undercarriage and used, one above the nose-end of the spacecraft and one under the engine cluster at the tail, for take-off and landing) suffers a mechanical fault and collides with the rear of the craft, damaging the escape unit circuit. With the crew unable to escape, it is again up to International Rescue to save the astronauts, as well as a town in the Zero-X flightpath, from disaster.
