Scott reports to his father that when he got to the scene of the fire, they'd managed to get it under control. He thought it seemed best to leave them to it. Jeff says what he did was right, and hopes there weren't too many casualties. Scott says he doesn't think so, and the police controller assured him that it wasn't as bad as it first appeared. Jeff asks Scott to take Alan up to the satellite later as soon as he gets back. Seconds after the call ends, Scott suddenly finds himself under attack by three fighter jets!

Scott takes evasive action, and pulls Thunderbird 1 up. He reports in that he's under attack from three unidentified aircraft. He manages to get away from one, but then another one moves in behind him and fires. The shot hits Thunderbird 1, causing it to go into a dive.

Scott reports he's been hit, and Jeff tells him to keep the nose up. Scott manages to pull up late on, but Thunderbird 1 crashes into a desert, and slide across the sand. It eventually comes to a stop.

One of the fighter jet pilots, who doesn't speak English, seems to report their mission has been a success. He is heard saying the word "Thunderbird", but then he and the other pilots withdraw from the area. Jeff tries to contact Thunderbird 1, but gets no response. Scott wakes up and has a gash on his head. He tries the radio, but it's not working. He supposes he should take a look outside.

He opens a hatch on Thunderbird 1, and takes a look around. But there's no sign of anything. He thinks he's 5,000 miles from base, and his radio is dead. His head injury then hurts, and he collapses. Back on Tracy Island, Jeff explains to Virgil about the situation. It looks like Scott has been shot down, so Virgil asks about the radio.

A tearful Tin-Tin explains the radio has gone dead, and Scott won't answer. Gordon says he's plotted Scott's position, and doesn't think Scott could have gotten far away from his last contact point. Jeff tells Virgil there's not a moment to lose, and sends him on his way. Brains says he's heard what's gone on, and has selected the pod they need.

In Thunderbird 2's hangar, pod 6 is selected. Tin-Tin wants to go, but Jeff tells her it's out of the question. Tin-Tin asks what good reason can there be to not let her go, and he says there's no knowing what Virgil and Brains are going to find when they get there. They can't ignore the possibility of another attack. Tin-Tin thinks they're going to find out there is Scott wounded, perhaps critically! He's going to need all they help that International can give him. Jeff tells her alright -she'd better get ready, as Thunderbird 2 launches in four minutes. Later on, Thunderbird 2 takes off.

Thunderbird 2 reaches 2,500 feet, so Virgil levels it out. Jeff tells them good luck. Gordon thinks this is some mystery, and Jeff agrees. He just hopes Virgil isn't going to be too late, and wishes he knew what it was that made those men shoot Scott down like that. Gordon thinks it must be hot out there in that sun. Jeff says there isn't another single, solitary soul within miles.

In the desert, explorers Wilson and Lindsey are driving their truck over the dunes. Lindsey tells Wilson to slow down -he's got to treat this sand with respect. Wilson says he hates the sight of sand. They've been 15 days in this god-forsaken desert, the sooner they're out of it, the better! He's fed up to the back teeth of this lousy expedition. Lindsey reminds him he wanted to come on the trip, and Wilson thinks he must have been crazy. As they continue driving, Lindsey thinks he's seen something, but a sand dune covers it up as they drive on. Wilson thinks he must be seeing things, it was a mirage.

But as they clear the dune, they come across Thunderbird 1. Lindsey asks who's seeing things now, but Wilson thinks this might be serious. They drive up to Thunderbird 1, and when they see the markings on it, they realize it's International Rescue! They then see Scott stretched out over the hatch, and thinks he's in a bad way. Scott then wakes up.

Lindsey tells him he's hurt, but he says he'll survive. Lindsey goes to get their first aid kit, as Wilson asks Scott what happened. Scott says he was on his way home when these three fighters appeared, and forced him down here. Wilson wonders who they could have been, as there's no human life here for miles and miles around. They should know, as they've been all over these parts. Scott asks them what they're doing here. Wilson says they're on an expedition to locate the lost pyramid of Khamandides. Lindsey says there were looking for it, until Wilson decided he's had enough. Scott says the locals aren't all that friendly, but then holds his head in pain. Wilson says they'll fix him up, but he asks them to do him a small favor first: radio International Rescue and tell them he's ok. Wilson asks for the frequency, but Scott says any frequency will do -they'll receive it.

Later on, John contacts Tracy Island with wonderful news about Scott. Jeff is relieved to hear that, and asks what happened. John says he hasn't got the full story yet, but it seems Scott had to make a forced landing. John then gives him the exact location Scott is in, so Jeff relays this to Virgil. Virgil says they're very near that area now.

They see Thunderbird 1 crashed in the sand. Tin-Tin sees the truck parked next to it, and Brains says it must belong to those guys who found Scott. Virgil lands Thunderbird 2. John asks his father what the latest on Scott is. Jeff says Tin-Tin has fixed him up, and Brains has repaired the radio. It had been smashed during the skirmish with those fighters. John asks if he has any ideas as to who the attackers were, but Jeff says no -it's a real mystery. John guesses Scott doesn't have to do his spell of satellite relief until he's fit. Jeff says they'll see tomorrow when they get home, as right now they're settling in for the night.

In the desert, the group have setup a camp. Scott thinks Tin-Tin's apple pie was good, and asks if there's any more. Tin-Tin tells him he's scoffed the lot, and three helpings is enough -he's supposed to be an invalid. Brains says that considering the brutality of the attack, he thinks Scott got off quite lightly. He's checked the radio and it's alright now. Scott says that if these guys decide to attack tomorrow, he thinks they'll find that they're more prepared. Tin-Tin asks if he thinks they might attack, but Scott isn't sure what to think. This whole thing has him baffled.

Wilson says it's this desert -he's had a strange feeling ever since they came out to look for this pyramid. Virgil says he didn't think there were any pyramids in this part of the desert. Lindsey says some explorers claim to have seen the lost pyramid of Khamandides, but others say it was just a mirage, and they just imagined the whole thing. Tin-Tin tells everyone that it's very late, and they have an early start tomorrow. The group all go to bed.

The next day, Thunderbirds 1 and 2 have returned to base. Grandma asks if he wants more coconut crumble, but Scott says he just couldn't. As everyone starts asking him questions, Jeff says that's enough for the time being. Scott can take it that they're glad he got home safe. Scott says he has them to thank for that, and those two other fellows. Tin-Tin is surprised they found him in that expanse of desert. Scott hopes they have as much luck in finding their pyramid.

Wilson and Lindsey are on the move again. Lindsey thinks it was certainly nice to have a chance of faces, wasn't it? Wilson says he gets his meaning, and he's just as sick of his ugly mug! But they'll soon be out of this desert. As he gets the truck to gain speed, Lindsey tells him to cut that out, as he's going too fast again. Wilson tells him to relax, and keep his mind on navigation. The truck drives up a large dune, but is still going fast. Lindsey pleads with Wilson to slow down, but Wilson tells him to quit whining, or he'll get sand in his throat. The truck then starts to slide, and Lindsey tells Wilson to pull round. Wilson tells him to shut up.

The cable connecting their trailer to the truck then snaps. The trailer rolls down the dune, and comes to a stop at the bottom. Lindsey calls Wilson a stupid fool, he knew this would happen. Wilson says all of their gasoline and water is in that trailer, so they've got to get it. But before they can, the trailer explodes, destroying everything. Lindsey asks what they can do, as they're over 300 miles from base camp. Wilson says he knows, and they've only got three gallons of juice left in the truck. They'll just have to radio base for help, but Lindsey then reveals he'd put the radio in the trailer.

They then see the radio in the sand, so Wilson checks it out. He says it has taken a pounding, but it could be ok. He attempts to contact their base camp, but there isn't any response. He thinks there's something wrong with the radio, so Lindsey says to bring it up here. Wilson then says that some of the sonic wave compensators have been damaged. Lindsey says they've got to get through somehow, as they're going to need water, otherwise they'll die.

At Tracy Island, Tin-Tin and Gordon want Virgil to join them in the pool. He says later maybe, but he's going to play tennis with his dad once Alan and Scott have taken off. Inside the lounge, Jeff tells Alan that it's time to relive John in the space station. Alan says he's all set, so Jeff asks Scott if he feels fit enough. Scott says he does, so Jeff says away they go. The sofa moves downwards.

Alan and Scott board Thunderbird 3, which takes off and heads into space. Back in the desert, Wilson keeps trying the radio, but says he guesses it's no good. Lindsey says he needs water, but Wilson tells him to quite moaning. Lindsey wishes the truck didn't have an air-cooled engine, but Wilson says it has. He says they'll have to think this thing out. They've got enough gas to take the truck around 50 miles, so which way should they go? Lindsey says that's a fool question, as there's always sand and more sand.

Wilson says there are water holes in the desert, and says he's found one on a map. It's 40 miles due north, so they decide to go to it. He tells Lindsey to keep working on the radio, as they drive off towards the water hole. In space, Thunderbird 3 arrives at Thunderbird 5, and docks with it.

Alan tells Scott he'll see him in a month. He goes through to Thunderbird 5, where John is waiting. John tells him to keep listening to a certain frequency. It's very faint, but he figures someone's in trouble, but he's not sure. Alan says that the signal is coming from the Sahara area. John thinks it might be the two archaeologists who found Scott. Alan says he'll keep watch. As John leaves, Alan hears someone on the radio trying to contact their base camp, and wonders what's happening down there.

In the desert, Lindsey says it's no good, nobody is answering. This heat is unbearable, it'll make him go crazy! Wilson tells him to take it easy, and asks if he can see that up ahead. Lindsey realizes that they've arrived at the water hole, so they drive up to it. But as they get closer, Wilson says to take a good, long, hard look at it -there's no water in it!

Lindsey says this can't be, there has to be water -otherwise they'll die! He says Wilson has to do something, otherwise he'll go crazy. Wilson tells him he's going to be ok, and says he'll try the radio again. Lindsey says base won't answer, but Wilson says they'll try someone else. He's got a crazy idea in his head, maybe it'll work, maybe it won't. Lindsey asks him what he's going to do, and he says he's going to call International Rescue. Scott had told them if they were in trouble, he'd be more than pleased help them out. Wilson makes a distress call, which is picked up by Alan in Thunderbird 5. But he can't talk back to them -what he says doesn't get through to their radio.

Thunderbird 3 arrives back and lands in Tracy Island. Alan reports in that he's received a distress call from the Sahara Desert, and thinks it was from those two guys who helped Scott. Jeff asks if they said who they were, but Alan says they didn't, and the call was very faint. They kept saying they were dying of thirst and then the call faded out. Virgil asks for the message to be replayed, and when he hears it, he confirms that was the guy. Just then, Scott arrives back from Thunderbird 3.

Jeff tells him to get down to Thunderbird 1 and standby for launching -one good turn deserves another. Scott asks what he means, but Jeff says he tell him about it once he's on his way. Scott goes to Thunderbird 1 and takes off.

Jeff tells Tin-Tin he only hopes Scott gets there in time. When a man is in the middle of the desert without water, he can be pretty desperate. Meanwhile, Wilson says the radio finally gave out. He doesn't know if he got through to International Rescue, and tells Lindsey they'll just have to wait and see. Lindsey thinks that with this heat and exposure, they'll be lucky if they last out for another hour. But he then sees something on the horizon, and asks what it is.

Wilson says he can't see anything other than sand and desert. Lindsey tells him to look over there, and then Wilson sees it -a pyramid! They realize they've found what they came all this way to see: the lost pyramid of Khamandides! Wilson says they've got just enough gas to reach it, and hopes there may be some nomad tribe camped by it with water. They start to drive towards the pyramid.

They stop at the pyramid, and Lindsey says it's fantastic. Wilson says it's deserted, and guesses finding anyone else in this lousy desert was too much to hope for. They get out of their truck, and see hieroglyphics on the walls. Lindsey is able to read them, and says that this is the great tomb of King Khamandides, the God of the Eternal Fountain. He says the Egyptians thought of their kings as gods, but Wilson thinks the eternal fountain bit is a laugh -it must have run dry. Lindsey says he can't see any door, but then one opens up in front of them.

They wonder how it opened, but can then hear water splashing inside the pyramid. They decide to enter it, and come across many statues inside the tomb. Lindsey thinks they're magnificent, but Wilson says so is the sound of that water. The door then closes behind them. Lindsey says there must be someway of opening it, and starts to feel along the walls.

Lindsey thinks he's found something, and tells Wilson to use his lighter. Wilson does so, only to reveal a skeleton! Wilson thinks this guy tried to get the door open, but never made it. Lindsey asks what they should do, as now they're trapped. Wilson says he knows what he's going to do: find that water! Meanwhile, Scott arrives in Thunderbird 1, and comes across the water hole. He reports that he can see jeep tracks heading north, so he's doing to follow them.

Wilson tries calling out to see if anyone else is there, but gets no response. The only other sound is that splashing water. They venture further on, and find what they were looking for: the Eternal Fountain. Outside, Scott arrives at the pyramid, and says he's found the jeep. But it has been abandoned outside, so he decides to go down and take a look.

Scott lands Thunderbird 1. Meanwhile, Lindsey says he's never tasted water like this, it's so sweet and cool. Wilson wonders how this water gets here, what is this place? Lindsey suggests they go deeper, as they could have made the archaeological discovery of the age! Wilson recalls that the Egyptians buried their kings with fantastic treasures, so maybe they'll find something that'll make this trip worth their while! Outside, Scott reports that the prints just end at a blank wall, and there's no entrance anywhere.

But then the door opens up. He tells his father he's going in, so Jeff tells him to be careful. Scott enters the pyramid, and then the door shuts behind him. He then hears Wilson and Lindsey's voices, so he tells his dad that the entrance has closed, but he can hear voices. Jeff says to check it out, if they don't hear from him within 10 minutes, he'll get Thunderbird 2 out there.

Wilson and Lindsey have found the treasure, and Lindsey says they're the richest men alive. Wilson thinks they could buy the world, but they says they've forgotten something: they're trapped in here. Lindsey says they can't be, they're too rich to be trapped! Scott then enters, and says International Rescue are at their service. But Lindsey says he can't fool him -he's here to steal their treasure!

Scott says they called them for help, which is why he's here. Lindsey responds by shooting his radio to pieces. Wilson asks what he shot at him for, Scott is here to rescue them! Lindsey says Scott only wants the treasure, which prompts Wilson to call Lindsey crazy. Lindsey responds by shooting at him.

Scott hides behinds a statue and tells Lindsey to throw down his gun, as he needs help. Lindsey tells him he's the one who needs help, as he's going to die! Scott tells him he's been through a tough time, and he'll get him to a hospital. Lindsey thinks that will give Scott the chance to get his treasure, so he fires at him. Scott says if that's the way he wants it, he'll just have to blast him out. The two start shooting at each other.

One of Lindsey's shots causes Scott to drop his gun, which falls down some steps. Lindsey is able to grab it, and then tells Scott he has him now. He starts firing at the statue, and tells him to come on out -he can't escape. He shoots the statue so many times it eventually falls over.

Lindsey tells Scott he has no more protection, now he will die! He starts laughing, but then two men from the Zombite clan appear in the room. One shoots at Lindsey, causing him to fall backwards and drop his gun.

The Zombites beckon to Scott. Wilson then gets up, revealing that he's still alive. He tells Scott it looks like these guys want them to go with them. He thinks they'd best do as they say. Meanwhile, Thunderbird 2 has been launched. Virgil says they'll reach the pyramid in 1.4 hours from now.

Jeff tells him good luck, and to take care when crossing that desert -International Rescue are depending on them. Back in the pyramid, Scott and the others are taken through some kind of plant via a monorail system. Scott says this is where these guys must get their fuel and power. It looks like some kind of mineral, that gives off an explosive gas.

Lindsey says this gas must be lethal too, and points out a guy below wearing a gas mask. Scott says that guy is tanking up those fighters, and those look like the craft that shot him down the other day. The monorail car continues into the next room.

Virgil reports that he's started to cross the Sahara now, but there's no sign of any trouble as of yet. He asks if there has been any contact with Scott, and Jeff says not a word -they keep trying to get through, but he just doesn't answer. Back inside the pyramid, Scott's group are taken to who appears to be the leader of the Zombites. A view screen is activated, showing Thunderbird 2 flying through the sky.

The leader seems to give out some kind of order, and Scott watches as the view screen displays three missiles! Wilson thinks these guys are going to attack, so they need to warn Virgil. The missiles are loaded into position, and head up into the pyramid.

The leader keeps ordering for the missiles to be raised higher. With everyone distracted, Wilson suddenly attacks the guard in the monorail car, causing him to drop his gun. Scott picks it up and starts firing at the other Zombites in the control room.

One of his shots hit the console the guy preparing the missile is using. This causes the missiles to launch prematurely, and they end up crashing into each other and exploding before they get to Thunderbird 2.

Virgil and Gordon see the explosion. Gordon thinks those missiles were too wide of the mark to be intended seriously, and thinks it could have been Scott trying to warn them. Inside the control room, the Zombites return fire. Scott tells Wilson to start the car, so he does. As an alarm starts ringing, the car begins to move off.

In the plant room, the Zombite worker sees the car and starts firing at it. Scott shoots at him, causing him to be knocked back and hit a lever down as he falls.

This releases a gas into the room, which soon leads to things exploding. Wilson says something is happening, and Scott says it's the pressure in the fueling pipes. He closes the car's door, as the car continues to move towards the other end of the room. He asks Wilson if he can get any more speed, as the gas is everywhere and this place is going to to up any moment! Wilson says this is the maximum. Things continue to explode in the room. Scott says they've got to warn Virgil to stay clear.

Virgil wonders what's going on inside the pyramid, as first there's a whole salvo of rockets, and then nothing. Gordon says they should go down and investigate, so Virgil prepares to land Thunderbird 2. Inside the control room, the Zombite leader seems to curse the Thunderbird, but then starts choking on the gas.

The monorail car makes it out of the plant room. Lindsey wakes up, and asks where he is and what's going on. Scott tells him he's woken up not a moment too soon, as in a couple of minutes he's going to have to run for his life like he's never run before.

Inside the control room, one of the Zombites collapses onto a control panel, hitting something that causes the pyramid's hidden door to open up. Scott tells Wilson and Lindsey to hurry it up, as they need to get out of here! They run out of the pyramid.

They arrive outside just in time to see Thunderbird 2 about to land. Scott contacts Virgil and tells him to keep away -he needs to regain height and keep away from the pyramid! He says it's about to go up at any moment. As Thunderbird 2 moves off, Scott, Wilson and Lindsey board Thunderbird 1. Thunderbird 1 then takes off, and heads away from the pyramid.

Part of the pyramid then explodes, destroying Wilson and Lindsey's truck. Virgil says there she goes, and Scott says the lost pyramid of Khamandides is lost forever now. More explosions then hit the pyramid.

Lindsey says to take a look at that -what an escape! Wilson says they've certainly got a lot to thank International Rescue for. As the pyramid continues to explode, it's soon completely destroyed. Thunderbird 1 and 2 head away.