DR Sandra Travers placed a bowl of freshly-made soup down on the table in front of her son Paul before sitting down opposite him to eat her own. Almost immediately she noticed that Paul seemed distracted. "You okay, Paul?" she asked. "You seem troubled by something?"

"Did Captain Taylor come and see you, Mum?" Paul asked.

Sandra frowned slightly. "No? Why? Was he supposed to?" she asked.

"Right at the end of today's lesson he started coughing rather badly," Paul said. "I suggested that he should come and see you, but he said he was fine."

Now Sandra was worried. "How bad was the coughing?" she asked. "On a scale of one-to-ten?"

"About nine," replied Paul.

Sandra took a mouthful of soup. "That doesn't sound right," she said. "Eat your soup, love, then we will go and pay him a visit."

Paul now looked uneasy. "Do you really think we should?" he asked. "I mean, er, he might not be too pleased if he found out I'd told you?"

"I'm a Doctor as well as the leader of this Colony, Paul," said Sandra. "The safety and welfare of all the people here is my number one priority. If Captain Taylor isn't right, then we need to make sure that we can make him better. Now eat up."

After finishing their soup, Sandra and Paul headed along the corridor towards Captain Taylor's living quarters. Paul reached the door first and pushed the buzzer by the side. They waited for Taylor to answer. But he didn't. A nod from his mother made Paul push the buzzer a second time, but there was still no response.

Sandra opened a small flap on the opposite side of the door. "Look away, Paul," she said. Paul did so as she typed in a special code on the concealed keypad that unlocked the door and it slid open. "Captain Taylor?" she called out as she entered the room.

They both looked around, puzzled. The room was empty. A lot of Taylor's stuff was there, but Taylor himself was nowhere to be seen. A quick check of the bathroom revealed that he wasn't there either.

"Where is he?" asked Paul.

"I don't know, Paul," Sandra replied. She activated her wrist-communicator. "Colony Control, this is Dr Travers. Do you read me?"

"Go ahead, Doctor?" said a controller on the other end of the line.

"Terry, have you seen Captain Taylor?"

"Negative, Doctor. Haven't seen him all afternoon. Want me to contact him?"

"If you could, or at the very least locate him in the base, please," said Sandra. "I need to speak to him as a matter of urgency."

The controller checked his computer to see whether Taylor's key-card had been used on anything. What he saw made him frown. "That's odd. He left the base twenty minutes ago in one of the Rovers."

"He has?" asked Sandra. "Which way is he headed?"

"South-East," said the controller. "And you know what's that way if he continues on his present course?"

Sandra went pale. "Damn right I do," she said anxiously. "The Frazer Gorge - the home of the Rock Snakes!"

5!

4!

3!

2!

1!

"Thunderbirds Are Go!"

"SEEING RED"

THE doors of the Colonel-1 Control Room hissed as they opened to let Sandra and Paul enter then hissed again as they closed behind them. Sandra walked over to her desk and sat herself down. "Terry, have you got me a link to the Rover?"

"Yes, Doctor. Go right ahead."

Sandra spoke into the radio. "Colony-1 calling Rover 2. Captain Taylor, this is Dr Travers. Do you read me? Over."

Captain Taylor had already driven for quite a few miles since leaving the Colony without telling anybody where he was going. He growled quietly to himself as he heard Sandra's voice over the radio. "Captain Taylor, this is Dr Travers. Are you okay? Come in, please? Over."

Taylor did not respond. Instead he simply reached across to the controls and pressed two buttons before turning his attention back on where he was going.

The pressing of the two buttons instantly was noticed by those in the Control Room. "What the?!" exclaimed Sandra. "He's turned off the radio!"

"That's not all he's done," added the Controller. "He's turned off the Rover's location beacon. Now we cannot track where he's going."

The situation was becoming more and more confusing and concerning, especially for Sandra. This was not like Captain Taylor at all. "What the hell's going on?" she wondered out loud. She then made a decision. "Paul, stay here with Terry. Terry, contact the vehicle bay. Tell them to get the other Rover ready and that I am on my way down."

"Yes, Doctor."

"Where are you going, Mum?" asked Paul.

"To go and look for him," replied Sandra as she left the Control Room.

The garage doors opened and the other Rover headed out with Sandra at the wheel. "Terry, I am on my way," she said. "Keep track of my movements at all times."

"Roger that, Doctor," answered the Controller. "But if I may ask, how do you plan to locate him?"

"Easy," replied Sandra. "I'm going to use the thermal-scanner to track the wheel tracks. There's nowhere he can go where I can't find him."

The Tracy Jet made its way across the Atlantic Ocean heading for England. Aboard were Jeff and Virgil. They were on their way to see Hayley and to see how she was getting on following the incident at the Tangmere Medical Training Base following the incident. This was largely because Virgil had not been able to relax as they hadn't heard anything from Hayley since they left.

"Do you really think something could have happened to her, Virgil?" Jeff asked.

"You remember what she said, Dad," Virgil replied. "Lieutenant Pierce really got mad with her when he learned that she'd called International Rescue against his orders."

"Which she was well right to do," Jeff pointed out. "That young man in the Digger would have perished for sure if we hadn't come to his aid."

"But she was confrontational with him, and from what we can tell, he doesn't take that well," said Virgil. "I am extremely worried about what he might have done with her if he returned."

"We'll soon find out," said Jeff. "There's the Isle of Wight. We'll be arriving at Base Tangmere in a few minutes."

Virgil nodded. "If he's laid a finger on her-"

"You'll keep your emotions and hands to yourself, Virgil!" said Jeff sternly. "We're not here to create any kind of trouble. Am I clear?"

"Crystal," replied Virgil grimly.

"And if Pierce is here, I will be the one to talk to him. Alone," Jeff finished.

Virgil said no more as the Tracy Jet approached the runway at Base Tangmere.

Upon landing, Virgil and Jeff headed for the Main Control Centre and approached a young female officer at the reception desk. "Good morning, sirs. May I help you?" she asked politely.

"I hope so, my dear," replied Jeff. "The name's Tracy. Jeff Tracy."

The woman's eyes lit up and she stood up out of her seat. "The Jeff Tracy?" she asked in awe. "It's such an honour to meet you, sir!"

Jeff smiled warmly. "The pleasure's mine," he said. "I wish to see the Commander of this base. Hayley Madison, I believe?"

The woman officer's beaming face immediately changed to one of confusion. "Who, sir?" she asked.

This reaction instantly caused Virgil to frown, but he kept his mouth shut.

"Really?" asked Jeff. "Then who is in charge?"

"Lieutenant Pierce, sir," said the woman. "He's in his office now."

"May I speak to him, please?"

"I, er, will have to check," said the woman. "One moment, please?" She got up from the desk and went to a dark blue door nearby and knocked.

"Come!" a man's voice called from inside. The woman opened the door and went in.

Virgil and Jeff exchanged glances. They said nothing, but could both tell what the other was thinking.

The woman then came back out. "You're in luck, Mr Tracy," she said. "He's got a few minutes so he'll be glad to talk to you."

"Thank you," said Jeff. He turned to Virgil and gestured to him to wait out there whilst he went in alone. Virgil did not want to, but he wasn't prepared to disobey his father's wishes.

Jeff walked into the office to find Lieutenant Pierce sitting behind his desk. The officer stood up and to attention before saluting. "Colonel Tracy. To what do we owe the pleasure?" he asked.

Not being in uniform meant Jeff was unable to return the salute. "Lieutenant Pierce," he said, holding out his hand for the Lieutenant to shake. "Pleased to meet you."

"Likewise," said Pierce enthusiastically. "Please take a seat. Can I get you a drink?"

"No, thank you. Too early in the day for that, Lieutenant," said Jeff. "Actually I came to visit someone on this base. A family friend."

"Oh, yes?" said Pierce. "Who's that?"

"Hayley Madison."

Instantly, Pierce seemed to jump a little and his pencil snapped in two. "H-Hayley Madison?" he asked.

"That's correct," said Jeff, pretending not to notice Pierce's reaction. "Is she about?"

Pierce began fumbling through papers. "I, er, don't believe she is," he said, sounding a little uneasy so Jeff was thinking. "There were a few of our students who went to Base Weald in Essex. That's the Commando Training Centre."

"And why would she be there?" asked Jeff.

"Well, the students here need to learn how to treat any battle injuries that the soldiers might sustain when out in the field," Pierce said, regaining himself. "I believe she was one of those who went."

"When did she go?"

"Early this morning." He glanced at his watch. "They should be there by now. I suggest you go there if you want to see her, Mr Tracy. Now, if you'll excuse me I have some urgent reports to fill out. As you may have noticed my base is a little worse for wear following an incident that took place here yesterday."

"I did hear something about an unexploded World War Two bomb that was found," Jeff remarked as he stood up. "But thank you, Lieutenant. Keep up the good work."

"T-Thank you," said Pierce as he began to get back to his work. He tried hard not to release any sweat that had been forming on his brow and hoped Jeff hadn't noticed.

Jeff frowned in the direction of Pierce as he left the office. He thanked the woman on the desk and left the building with Virgil following close behind.

"Well?" Virgil asked anxiously.

"Base Weald, Essex," replied Jeff. "That's where we're going."

"Is that where she is?"

"That's what he said."

"But you don't believe him?"

Jeff didn't answer for a second. "Honest answer, son. I'm not sure that I do. He got rather edgy as soon as I mentioned her name."

Virgil began to feel sick. "Shouldn't we have gone to Colonel Casey about this?"

"She's still on leave, Virgil," Jeff reminded him. "But we're gonna go and check out this Commando Camp first. If Hayley's not there, then there really is something wrong, and we will bring her in."

Virgil's stomach felt like a washing-machine. As they headed back to the Tracy Jet, he could almost sense that Hayley was nearby, yet was nowhere to be seen. Little did either of them know that Hayley was a lot closer than they thought, imprisoned in a holding cell, directly underneath the path that they were walking on. As she lay on the small bed in the non-lit room, she heard the sound of footsteps walking overhead. She looked up, almost sensing that one of them was Virgil. She wanted to call out, but realised he wouldn't hear her. Instead she laid her head back down on the pillow and shed a tear.

Sandra stopped her Rover at the top of a hill overlooking the valley that led down to an area of Mars known as Frazer Gorge. It was here that aerial satellites had detected a very large quantity of Rock Snake formations. A few discrete expeditions had been made to the edge of the gorge and drones had been sent out to document where they were all located, but both Sandra and Taylor had made it very clear not to disturb the snakes in any way. From what they'd learned of them so far, they only seemed to wake up if disturbed.

Down below she could just make out Taylor's Rover driving towards the start of the passageway that went through the gorge. "Dr Travers to Colony Control. I have a visual with Captain Taylor. He seems to be going into the gorge itself!"

"Is he crazy?" answered the Controller. "If the snakes wake up-"

"He'll be fried for sure," said Sandra. "I have to stop him." She revved the Rover's engine and set off in pursuit.

Taylor had been driving slowly towards the edge of the mountains. He then brought his Rover to a stop and began to survey his surroundings. In the dusty, reddish-brown landscape that stood around him, he could just make out the darker-coloured formations that were easily identifiable as the sleeping Rock Snakes. He held a firm grip on the wheel. "Well…you've had a good run, Taylor," he said out loud to himself. "But I guess it is time for my swansong." Just then his eye caught something in one of the rear-view mirrors. He realised it was a light. Turning his head round to look, he realised that a second Rover was heading towards him. "Grrrr! Travers! Confound her!" he cursed. He then revved his Rover's engine to the max, spun the rear wheels that kicked up a huge amount of dust and then rocketed forwards towards the gorge with Sandra having to at first dodge around the dust cloud before continuing the pursuit.

The two Rovers raced into the Frazer Gorge and began negotiating the narrow and tricky curves and long straights that passed through it. Sandra couldn't understand what Taylor was doing. Surely the vibrations caused by their vehicles would wake the snakes up, she thought. But at a glance, none of them seemed to be.

They reached the end of the gorge without any of the snakes waking at all. This seemed to frustrate Taylor who spun his Rover around and then doubled back into the gorge again, much to the confusion of Sandra. "CAPTAIN?!" she yelled over as they passed. "LEE, FOR GOD'S SAKE! WHAT ARE YOU PLAYING AT?!"

Taylor couldn't hear her having turned off the radio in his helmet. He just gave her a look as he raced past and back into the gorge again. Sandra sighed heavily as she turned her own Rover around and went back in after him.

A second pass through the gorge still didn't disturb the snakes and they continued sleeping as though it was just another day. This infuriated Taylor, and was even more annoyed when he spun to come back round for a third run only for Sandra to stop her Rover right in the narrow entrance to stop him from coming in again. He banged his fist on the wheel in frustration before he caught sight of a sleeping Rock Snake nearby a few metres up from where they were. Taylor therefore stepped out of his Rover and began to climb the rocks towards it. Sandra got off her Rover and chased after him. "LEE? WHAT THE HELL ARE YOU DOING?!" she called up to him.

Taylor soon reached a spot nearly level to where the Rock Snake was sleeping. He ignored the fact that Sandra was climbing after him and opened up a zip on his suit. He placed a hand inside and pulled out a piece of rock he'd collected several months earlier. "COME AND GET ME YOU SLEEPING SCOUNDRELS!" he roared as he threw the rock at the sleeping formation. It hit the largest piece on the top of the coil and bounced off.

Sandra saw this and stopped dead, horrified by what she was now seeing. It had not been more than a few seconds since the rock had hit the top of the snake's head, but immediately it was starting to wake up. Its head began to rise upwards and as it turned towards Taylor, its eyelid began to open up revealing its sinister single glowing red eye which was now looking directly at the Captain. Taylor then opened his arms, like he was inviting it to take a shot at him.

"WELL, COME ON!" Taylor shouted at the snake. "WHAT ARE YOU WAITING FOR?"

The snake let out a low hiss as it continued to stare him down. But then its eye began to close and it started to turn its head away, lowering it as if it was preparing to go back to sleep again.

Taylor went red with fury. "GODDAMN YOU!" he bellowed, bending down to pick up another small piece of rock before throwing it at the snake. It struck the side of its head and bounced off. This time the snake let out a much louder snarling hiss as its eye snapped fully open and it turned its head back towards Taylor. It lifted its head higher as well until it was towering above him, and its eye seemed to turn redder with anger.

Sandra had never seen a Rock Snake in person and up until this point had been practically frozen with fear by the sight of it. But now she snapped out of it, realising now what was going to happen. Taylor opened out his arms again, to receive his final demise. "NO!" cried Sandra and lunged forwards. She grabbed Taylor's outstretched arm and yanked him away just as the Rock Snake spat its first fireball at them. It struck right where Taylor had been standing and obliterated the rocks around it. The blast hit Taylor and Sandra and sent them both tumbling down the short slope back to the base of the gorge floor. The snake watched them tumble and then it let out a loud shriek which was a call to all the other snakes in the area that they had intruders. As Sandra picked herself up off the ground, she looked around, eyes wide as the other Rock Snakes were now starting to wake up as well. "Oh, my God!" she gasped before grabbing Taylor who had only just managed to pick himself up. " COME ON, RUN!" she yelled as a Rock Snake on the opposite side of the gorge fired a fireball of its own down at them. It missed them, but instead struck the Rover that Sandra had been driving and it exploded instantly. Sandra dragged the dazed and stumbling Taylor towards the Rover that he had been driving, but a fireball fired from the first Rock Snake swiftly destroyed that one as well. Realising there was no way they could outrun the angry snakes which were now starting to unravel themselves as though they were going to chase after them, she knew they needed to find somewhere to hide. Looking around, she spotted an open cave entrance a few yards away. "COME ON!" she cried again, dragging the Captain into the cave.

It was pitch black but before she had a chance to find a torch, the ground disappeared under their feet. "AAAAAAAAAAAAAAARRRRGGGHHH!" they both yelled as they fell down through the blackness before reaching the bottom and landing in a vast cavern down at the bottom. Sandra landed first and felt a hard bump on her back as she landed heavily. Taylor then landed and cried out in agony as a SNAP could be heard as his leg went off in an awkward direction.

It took a few moments for Sandra to regain her senses and recover herself. She looked around as she took in their new surroundings. It was dimly lit but there was an eerie red glow that filled the cavern. Spikes of rock could be seen poking down from the top like vicious icicles. Standing up, slowly and awkwardly due to her back now feeling very sore, she took out a torch and shone it around the cavern. She gasped at what she saw in front of her - a massive underground lake made up entirely of red-coloured water. "My God…" she gasped in a mixture of awe and fear. She then turned around and her torch shone on Taylor, and she then noticed his leg. She ran over and began to run a medical scan. She then reached over to his helmet and pressed the button that activated the radio on the side of his helmet. "Hold still, Captain," she said. "Your leg is broken."

Taylor merely groaned in response.

The Rock Snakes had begun to gather around outside the small cave entrance, curious to know where the two intruders had gone. The first one that Taylor had thrown rocks at lowered its head right down and tried to peer inside the cave. It couldn't see anything and lifted its head back up before exchanging looks with the second one that had attacked and a third one that had come down to join them whilst the others remained on their various perches and observed. The three snakes seemed to communicate with some kind of hissing noise and the other two then moved away to return to their resting places whilst the first one stared outside the entrance. It then lifted its head up at the rock-face above the small entrance and fired another fireball at it, dislodging a large amount of rock and causing a landslide which completely blocked off the entrance, trapping Sandra and Taylor inside. The snake seemed satisfied that the intruders were no longer a threat and began to make its way back to its own resting place so it could go back to sleeping again.

Deep down below, Sandra felt the rumbling of the landslide and looked around in terror, fearing that the cavern they were in was about to collapse. Fortunately it wasn't and she could breathe a little easier. She knew that they were trapped and weren't going to be able to get out without assistance, and she also knew that that assistance couldn't be provided by the Colony. She could only hope that her radio wasn't damaged. "Dr Travers to Colony Control. Are you receiving me? Over." The radio fizzled and crackled but there was no reply. She adjusted it in the hopes of getting through. "Colony Control, come in please? Over!"

The radio continued to fizzle, but this time she thought she could hear a faint voice coming over it. "Mum? Mum, can you hear me?"

"Paul!" Sandra cried in relief. "Paul, is that you? Can you hear me?"

"Just about, Mum," Paul answered over the radio. "But your voice is very weak. Are you okay? Where are you?"

"Paul, I need you to listen to me,' Sandra said. "I'm fine, but Captain Taylor's badly injured. We're in an underground cavern and there's a large underground lake down here. We can't get out as there are Rock Snakes outside. Paul, I need you to call International Rescue. We need help immediately. Have you got that?"

"Don't worry, Mum," Paul said, doing his best to sound reassuring. "They'll get you out of there. I will call them right away!"

Sandra smiled. "Well done, Paul. I love you." Just then she happened to turn to her left and then reacted when she saw Taylor was no longer where he'd been moments earlier. Looking around, she was horrified to see that he was dragging himself towards the lake. Hastily signing off her radio, she hurried to stop him by standing between him and the lake. "And where the hell do you think you're going, Captain?" she demanded.

"Move, Doc," growled Taylor weakly. "I need to get in that lake."

"Are you crazy?!" snapped Sandra. "Actually, why am I even asking that? I know full damn well that you've gone crazy! You threw rocks at a goddamn Rock Snake! What's the matter with you, Taylor? ARE YOU TRYING TO GET YOURSELF KILLED?!"

"YES, GODDAMNIT, I AM!" bellowed Taylor, causing Sandra's mouth to fall slightly open. "AND I'D BE DEAD BY NOW IF YOU HADN'T-" That was as far as he got before he started coughing heavily and laying flat down on his front.

Sandra bent down and held onto him as he continued to cough almost uncontrollably. She was deeply disturbed by first what she'd just heard, and secondly the amount of coughing he was doing. She'd originally been concerned when Paul said he'd heard Taylor coughing back at the Colony, but she hadn't expected it to be as bad as this. Once the coughing subsided, she rolled Taylor over onto his back for he'd gotten too weak to try and move again. What she saw her made her eyes nearly pop out as she let out a low, horrified gasp at the many little splatters of red that was now on his visor. "Oh…my…God…" she said in a soft voice. The anger she'd had towards him was now gone, and real fear for his life had replaced it instead. She held onto his hand and looked up at the roof of the dim and sinister cavern they were in. "Please hurry, International Rescue," she said.

The Controller had allowed Paul to sit in his chair whilst he'd been talking to his Mum and had now made the correct adjustments to the set in order to send out a distress call. "Okay, young man. It's all yours."

Paul nodded his thanks and spoke urgently into the radio. "Mayday! Mayday! Mars Colony calling International Rescue. We need immediate assistance. Over?"

Millions of miles away, orbiting the Earth, Thunderbird 5's powerful receivers picked up the distress call. John had been taking a nap inside the space-station but was soon woken up by EOS setting off his alarm.

"John, wake up! We're getting a distress call," EOS said.

John groaned as he sat up. "Can't you take it, EOS?" he asked sleepily. "You've done it before."

"I thought you should take this one, John," EOS said. "It's coming from a young boy on Mars."

John suddenly snapped awake. "Mars?" he asked. "A young boy?" He stood up. "Okay, you have me, EOS. Put him through."

EOS did so and a hologram of Paul appeared from the projector in John's room. "Calling International Rescue - this is Paul Travers calling from the Mars Colony. Can you hear me? Please respond."

John pressed a holographic button to take the call. "This is International Rescue. I'm receiving you, Paul. What's the situation?"

"Oh, please, you've got to come!" begged Paul. "My Mum and Captain Taylor are trapped in a cave in where the Rock Snakes are. There's a lake, and Captain Taylor's injured and sick and I-"

"Woah, woah, woah, slow down, Paul! Take a breath," soothed John. "Slowly please."

Paul whimpered and John noticed tears coming from his eyes. "Please, Mr Tracy," he pleaded. "Captain Taylor is very sick. I think he might be dying. And…I want my Mum back."

John's blood ran cold. He knew action was needed and fast. "Okay, Paul, we're on our way," he said. "Now you need to be strong and brave. I know you're scared for them and you've every right to be, but I need you to be a brave boy right now. Do it for your Mum. Can you do that?"

Paul did his best to swallow his fear and nodded. "Yes, sir. I can do that," he promised.

John smiled. "Good man," he said. "Now if you'll excuse me. I must get the others launched."

Paul nodded again. "Please hurry," he said and John signed off.

John turned to EOS's camera. "EOS, I need you to run a thorough scan of the Frazer Gorge on Mars," he said. "Captain Taylor and Dr Travers are in that area somewhere underground. I need you to try and locate them and determine what kind of situation we are dealing with so I can launch Thunderbird 3."

"Understood, John," said EOS as she brought up a large hologram image of Mars. She soon selected the Frazer Gorge and began the deep underground scan. She soon had mapped out the region both above and below the ground to show John what it looked like.

"Woah!" remarked John. "That's not a lake. It's an underground water-system! It goes on for miles."

Then two green lights appeared on a specific part of the scan where the main water section was. "I have found them!" said EOS. "But I'm detecting one is rather weak."

"That must be Taylor," said John. "And Paul said something about him being sick. We have to get out there fast."

"A job for Thunderbird 3 then?" said EOS.

John looked carefully at the scan image. "Not entirely, EOS," he said as he reached out to the holographic communications wheel to contact Tracy Island. "The terrain above them is too mountainous for the drill of Thunderbird 3 to burrow down to them. I'd say this is gonna be a job for Thunderbird 4!"