A fire is raging at a mine. International Rescue are on the scene already, as Scott and Virgil move their own fire truck in towards the mine, where some other fire engines are pouring water over the blaze. Nearby, Thunderbird 1 and Thunderbird 2 have been left unattended.

Next to where the Thunderbirds are is a house. Inside, Chip Morrison is being put to bed by his father. He tells him to get settled down for the night, but Chip asks how can he during all this excitement? His father tells him he'll just have to try, as he has to go over there and help with the fire. Chip asks what International Rescue is doing, and his father says they're going to go down the shaft and bring up the men below. He says that's enough questions, and tells him to be a good boy and get off to sleep -it's not like he has a mother to look after him, so he must not let him down.

As he leaves, the fire continues to rage. Chip gets out of bed and opens up the blind. He looks at the fire, but then looks over at Thunderbirds 1 and 2.

Sometime later, the Thunderbirds are returning to base. Jeff tells Scott that he just heard a newscast about the fire. Scott says it was quite a blaze. He then arrives back at Tracy Island first, and lands Thunderbird 1.

Virgil tells his father to ask Brains to standby, as Thunderbird 2 has developed a fault in the electrical system when they were at the fire. Virgil then arrives back at the island, so he slowly flies Thunderbird 2 down the runway and turns it around. He then has Thunderbird 2 roll backwards and enter the hangar.

Jeff hears a security alarm go off. He tells Virgil to hold everything and under no account release the pod. He then tells Gordon to contact Scott and all rendezvous in Thunderbird 2's hangar. Virgil and Alan don't know what's going on, but they shut down Thunderbird 2. Alan asks what now, but Virgil tells him they'll just have to sit tight.

Jeff and the others enter Thunderbird 2's hangar. Jeff tells Scott and Gordon to stay where they are and cover the pod's entrance. Jeff then tells Virgil to release the pod and lower the flaps, as there is a saboteur onboard. Virgil raises Thunderbird 2 up, revealing pod 1. He then has the pod's flap move down.

The pod door opens, so Jeff says he knows someone is in there. He tells them to come on out, or they're going to blast them out. There's no response, so Jeff tells them that they'd better move, as they don't stand a chance. After a few seconds, Chip appears, asking them not to shoot -he didn't mean any harm!

Almost everyone goes back to the lounge, where Jeff starts yelling that this shouldn't have happened. He thinks the Thunderbirds shouldn't have been left unguarded, this shouldn't have happened and that's all there is to it. This constitutes as a security hazard, they've got a boy here at their base and he's got to be returned to his home. He's seen them all and he's seen their location. He asks Scott and the others what they should do, do they have any bright ideas? They stay silent, so Jeff asks where the boy is now. Scott says Virgil is taking care of him, so Jeff hopes Virgil is keeping his mouth shut. Meanwhile, Virgil and Chip are in Thunderbird 2's hangar. Chip says Thunderbird 2 is enormous, and asks if this is the machine that Virgil flies. Virgil says they have very strict security here, he can't tell him anything.

Chip says he understands. He reveals that when he grows up, he wants to be a member of International Rescue, but he'd like to fly Thunderbird 1. Virgil asks why Thunderbird 1. Chip says he imagines it's faster and more important. Virgil says that without Thunderbird 2, none of the rescues would be possible. For example, take the time they went to save Eddie Houseman...

Virgil explains to Chip about what happened with Eddie -he went up to a mountain trying to build a road through it. Progress was held up by a series of earth tremors, but Eddie didn't want to give up so easily. He ignored warnings about the dangerous landslides and went off to blow up parts of the mountain with some charges. When his truck got blown back by one of the explosions, it was in danger of tipping over, and to make things worse, he still had a case of charges onboard. International Rescue were called in, and Thunderbird 2 got Eddie to safety by carrying his tractor away.

Back in the present, Virgil tells Chip that another mission was successfully completed, so they set off for home. Chip wishes he'd been there. Alan then comes in and tells Virgil that their father wants a word with him in the lounge. As Virgil leaves, he asks Alan to take care of Chip. Chip says he liked Virgil, as he told him all about Thunderbird 2. Alan says Virgil shouldn't have done that, but he'll tell him one thing: he's not going to get anything out of him nothing about Thunderbird 3. Chip says Alan must be the pilot of Thunderbird 3. Alan admits that he is.

The two go to Thunderbird 3's launch bay. Chip says this is a spaceship, and asks how fast is travels. Alan says it's a secret, so he can't tell him. Chip says Virgil told him all about Thunderbird 2, and Alan says he shouldn't have. Chip says that with Alan being a spaceman, he doesn't get so involved in the rescue operations. Alan says when Thunderbird 3 blasts into space, he's the one that's in charge! Does he remember about that Sun Probe rocket that started heading straight for the sun? Chip tells him to go on...

Alan tells Chip the story of the Sun Probe -a rocket which blasted off from Earth on a mission to collect fragments from the sun itself. The probe was fired and collected the fragments before returning to the main rocket. However, the Sun Probe's retros didn't fire, requiring International Rescue to launch Thunderbird 3 and use its safety beam to fire the retros instead. Thunderbird 3 then fired its own retros, as Alan and the others headed for home.

Back in the present, Chip says that was some rescue operation. He tells Alan he certainly is a member of International Rescue. Scott then appears and tells Alan that their father would like a word with him. In the lounge, Jeff says this is an impossible situation. Alan then walks in, so Jeff asks him how the kid is.

Alan says Chip is fine, he left him with Scott in Thunderbird 3's silo. Jeff wants to know what he was doing there, and Alan is about to explain, but Jeff says he knows already -Alan didn't tell Chip a thing, right? Jeff says that at least Chip is with Scott now, so he won't get anything out of him. But Scott has already got Chip in Thunderbird 1. Chip calls it a great machine, and Scott thought he'd like it. He can remember the first time he sat there for their first mission. His brother John radioed in from the space station that Tin-Tin's aircraft, the Fireflash, had been sabotaged and couldn't land because a bomb had been placed in the landing gear. So he dashed off to London and set up his mobile control headquarters in the tower at the airfield...

Scott tells the story of International Rescue's first emergency call. Arriving at London Airport, Scott organized the rescue of the Fireflash. When Fireflash came into land, it did so with its landing gear up. Virgil operated three elevator cars, two of which were remote controlled. Fireflash landed on these vehicles, and did so without the bomb going off.

Back in the present, Chip says that must have been exciting -he could picture the whole thing! Scott asks him to keep it to himself. Chip says of course, but now all that's left is Thunderbird 4. He's really looking toward to seeing that, but Scott tells him not so fast. He knows too much already, and it's no good looking disappointed. The answer is no -absolutely, definitely no!

But Chip soon finds himself in pod 4, at Thunderbird 4's controls. He tells Gordon that it's quite small compared with the others. Gordon says maybe it is, but it's a very necessary part of International Rescue. Chip thinks Gordon must only be involved in underwater rescues, like when someone's trapped in a submarine, and that can't happen very often. Gordon says he's involved in all types of rescues, but he can't tell him about them. Chip says he remembers that one at Allington Bridge. Gordon says that sure was a tough one... who would have thought at the time an underwater craft would be used to save a Martian Probe rocket...

Gordon recalls what happened at the bridge. The rocket was being transported to the launch site, and had two engineers inside it. As it slowly crossed the bridge, the weight was too much for the bridge to take. Part of the bridge ended up collapsing and the rocket fell into the water. It landed at the bottom of the sea, but its automatic countdown was activated, meaning it would blast off soon. International Rescue were called in and Gordon managed to knock away the rocket's nosecone, which is where the engineers were. With them saved, the rocket took off and exploded shortly after leaving the sea.

Back in the present, Chip says International Rescue had done it again. Later on, Scott says their father is really blowing his top. Alan wants to know where Chip is now, but Virgil says he doesn't know -don't ask him! Scott says if Chip is roaming around the base on his own, their dad is going to go berserk! They've given away too much information to Chip already, so he suggests they start a search. But Gordon then tells them to just take a look at this.

In the lounge, Chip is in Jeff's chair, as Jeff casually tells him that an operation of that size takes quite a lot of organizing. Chip asks if he controls everything from here, and Jeff says that's right. He's only got to push one of these buttons and it's Thunderbirds are go! It's quite an organization. Scott and the others are all amused at this. Later on, Jeff asks what they're going to do. They have to get the boy back to his home and prevent a security leak.

Jeff comes up with an idea. Chip is from England, which is almost directly on the other side of the world from their base. Instead of being asleep at home, he's been awake here at the base. When it's night in England, it's day here, which means right now, Chip must be a very tired little boy. Jeff starts going through his plan, which the team start carrying out. First, they put Chip to bed. Since the kid has been awake for 24 hours, he'll sleep like a log. Then, they'll transfer his bed to Thunderbird 2.

Thunderbird 2 heads to England at top speed, and arrives back at the danger zone before dawn breaks. As Chip got out of his home undetected, Scott and Virgil are able to get him back in undetected. Jeff is betting that if all goes well and the operation is completed successfully, the boy will wake up in the morning and think the whole thing has been a dream.

Chip's father arrives back home. Chip wakes up, asking if it's Mr. Tracy. But he see it's his own dad. His dad says that International Rescue team were fantastic. Chip says he knows, he should see their base and the Thunderbird machines! His dad asks him if he's been dreaming again, and he supposes so.

But he then says it seemed to real. Meanwhile, Scott reports from Thunderbird 2. He says that the mission has been successfully completed, and security hazard: negative. Thunderbird 2 heads back home.