The lead characters are ex‑astronaut Jeff Tracy, founder of International Rescue, and his five adult sons, who pilot the organisation's primary vehicles: the Thunderbird machines.
In the clip show "Security Hazard", a young boy stows away on Thunderbird 2 during a rescue operation and the Tracys unwittingly fly him back to base.
and "The Cham-Cham" had gone over‑budget and over‑schedule, the writing team reworked the next episode to feature a large amount of recycled footage, thus limiting the need for new scenes and making up for the extra time and money spent on the previous two instalments.
Curious about International Rescue, Chip moves to his bedroom window and gazes out at the open pod door of Thunderbird 2, which is sitting unattended in a field.
When Jeff's control panel warns of a stowaway aboard Thunderbird 2, the Tracys rush to the hangar and confront the intruder: Chip Morrison.
Furious at this security breach, Jeff holds an urgent meeting with his sons to decide what to do about Chip, but no one knows how to get the boy home safely without him revealing International Rescue's secrets to the wider world.
and "The Cham-Cham" finished behind schedule and over budget, forcing the series scriptwriters to come up with a way to make the next episode quickly and cheaply with only a limited number of new scenes.
Hearn also notes that Chip is one of a "curiously large" number of Supermarionation child characters who appear to have been raised by single fathers, and lack mother figures in their lives.