Elle and Heidi had had their eyes shut as they huddled together inside the cave. When the rumbling subsided, they opened their eyes only to find themselves in pitch blackness.

"Err, Heidi…" Elle said nervously. "What's just happened?"

Heidi tapped the face of her watch which produced a bright light so that they could see each other's faces. Then she shone it towards the entrance. They froze and stared wide-eyed. The cave entrance was completely blocked by the snow that had fallen.

"Oh…" said Heidi. "That's not good."

Elle was very scared now. "Oh, God – we're trapped!" she wailed, shaking with terror. "They'll never find us in here!"

Heidi felt scared too, but then she remembered who she worked for. She took some deep breaths and calmed herself down before turning to Elle. "Elle, listen to me. I need you to stay calm. It's the only way that we can get through this. Can you do that for me?"

"I…I'll try," stammered Elle. "But what about my show tonight?"

"Right now, that's not important," said Heidi. "What is important is that we stay alive until we are rescued."

"But how will anyone find us behind all that?" Elle asked, looking at the snow blocking the entrance. "Nobody even knows where we are."

Heidi looked down at her watch. "Then its lucky for us that I have friends who can do just that," she said as she pressed the face again. This time it began to send out an emergency beacon which she hoped would be picked up by Thunderbird 5.

John was impressed with the way Thunderbird 5 was maintained. "Well, Kerry, I can happily say everything here is more than perfection," he said.

Kerry beamed. "Thank you, John," she said happily. "That really means a lot coming from you."

John smiled. "I'd best get back to island and write up my reports along with the others," he said. "I also want to be there to see when Scott gives Alan a talking to." He added with a wink.

Kerry chuckled, but before she could answer, Kelly interrupted with some worrying news.

"Kerry, I might have something," Kelly said. "I'm picking up a distress beacon from somewhere in the Swiss Alps. I'm not certain but it sounds like one of our own signals."

"Put it on the speaker, Kelly," Kerry said. "Let's hear it."

Kelly complied and the others listened. The distinctive urgent beeping sound was one that they all recognised.

"One of our agents?" asked John.

"I can't think who though," replied Kerry. "We don't have any working in that area." She checked the signal on the holographic map whilst the others tried to figure out whose signal it was. "I can't get a firm lock on it," Kerry said. "There's too much interference from the mountains."

Katrina let out a small gasp. "Oh, God! Kerry, I know whose signal it is," she said. "It's Heidi's!"

Kerry's blood ran cold. "Heidi?! Oh, my God!" she gasped. "I need to inform Daniel right away!"

Daniel and the others were surprised when Kerry contacted them via the emergency channel.

"Daniel, we have a situation!" Kerry said.

"We do?" asked Daniel. "What is it?"

"We're picking up an emergency beacon from the Swiss Alps," said Kerry. "It's Heidi!"

"Heidi?" Daniel repeated. "But she's…oh, no!"

"What is it?" asked Scott.

"She was flying to Geneva aboard the private plane of Elle French and her band!" Daniel realised. "Something must have gone wrong!"

"We need to get out there and find her then!" said Laura jumping to her feet.

"Yes, you do," said Kerry. "I'll try and pinpoint her location."

"Can we do anything to help?" asked Gordon.

Daniel thought for a moment. "Actually, yes," he said. "With Adrienne and Beth still in space, we're two short for this mission. Virgil, could you and Gordon join us in Thunderbird 2?"

"We most certainly can," said Virgil.

"And Scott can come with me," added Laura.

"Then let's move!" said Daniel.

Laura hurried over to the revolving wall panel that led to the revolving elevator that would take her down to Thunderbird 1. After having turned through the wall and standing on the elevator, robotic arms attached her uniform to her as it went down. At the same time, Katie, Rosie, Jodie, Leanna, Wizzy, Sian and Cassidy hurried out of the lounge to make their way down to Thunderbird 2 whilst Daniel hurried over to the large rocket painting on the wall. He leant back against it and it began to tilt backwards sending him sliding down into a harness which took him down a long green tunnel. Robotic arms worked to attach his blue uniform with green utility sash as he went down. Once all that was complete, the rail his harness was on moved from the bottom side of the tunnel to the top side. Laura was now in her uniform and being carried out on a retractable walkway to Thunderbird 1. She sat down in the seat which was then moved inside before the hatchway sealed. She was shortly joined by Scott who'd got into his own suit via one of the other express elevators leading to the silos. His uniform was exactly the same as Laura's was. He took his position in one of the seats located underneath Laura's and strapped himself in. The trolley that Thunderbird 1 stood on began to move taking Thunderbird 1 up the diagonal tunnel towards its launching bay under the swimming pool. Daniel then reached Thunderbird 2's silo and swung down through the hatch in the top before closing the hatch behind him. He hurried to his seat and sat down before selecting Pod 2 on the computer. The pod conveyor activated moving Pod 1 underneath. Once Pod 2 was in position, the main body of Thunderbird 2 was lowered down onto it. Whilst all this had been going on, Virgil, Gordon, Katie, Wizzy, Leanna, Cassidy, Sian and Rosie had travelled down express elevators from the mansion to the silo and like Daniel had been changed into their uniforms on the way. Virgil's was also exactly the same as Daniel's and Gordon's was identical to Wizzy's. They were now able to join Daniel in the cockpit and were ready to go. Katie had agreed to let Virgil have a turn at the controls alongside Daniel. The rocks concealing the entrance to the hanger were lowered to allow Thunderbird 2 to taxi out onto the runway. As it came out, the palm trees were tilted back to allow it to pass. Up by the house, the swimming pool was opening up ready for Thunderbird 1 which was just coming into position on the launch pad. Thunderbird 2 was now on the launching ramp which lifted up into position. The wings folded into position and the blast shield rose into place behind the rocket engines.

5…4…3…2…1!

The rocket engines of Thunderbird 1 fired and it lifted up off the launch ramp, though the gap where the swimming pool had been before climbing high into the clear blue skies above Tracy Island. Thunderbird 2's own engines fired and it lifted up off the ramp to join its sister-ship.

"Thunderbirds are go!" said Daniel as they headed towards Switzerland.

Elle shivered. She was just as cold as she was scared. Heidi was looking around the cave to see what she could find. Incredibly, she managed to find some pieces of wood lying around and piled them up in front of Elle. She then took out an old cigarette lighter and tried lighting it.

"Do you smoke?" Elle asked.

"Never," Heidi replied. "I use it to light candles!" The lighter came on and she used it to start the wood burning. not only would this give them warmth, but it would also allow them to see their surroundings a lot more easily.

"Oh, warmth!" gasped Elle moving closer to the fire and holding her hands out. "My God, I could jump into it!"

"Please don't," said Heidi, sounding a little anxious. "They'd be no point in them rescuing us if you did."

"Who?" asked Elle. she looked at the blocked cave entrance. "Nobody's going to find us in here."

"They will, trust me," said Heidi. "My colleagues will be on their way by now...I hope," she added quietly to herself.

Elle was puzzled. "Your...colleagues?" she asked. "Are they from a rescue team?"

"You could say that, yes," said Heidi. but she didn't say any more on the subject. Both remained huddled together close to the fire in a desperate attempt to warm themselves up.

Thunderbirds 1 and 2 raced as fast as they could above the ocean whilst Thunderbird 5 moved orbit to get closer to Switzerland. Kerry was scanning all local frequencies trying to learn more about the situation.

"You got anything for us, Kerry?" Daniel asked.

"I've been listening in and it's not sounding good," Kerry replied. "The plane that they were travelling in has crashed. The local emergency services are on the scene and attending to the survivors. however, they're saying six people are unaccounted for - including Elle French."

"And Heidi must be one of them too otherwise she would've called us," said Daniel. "Okay, Kerry, keep monitoring and let me know what else comes up. Our ETA to the area is fifteen minutes."

"Make that ten for me," said Laura from Thunderbird 1.

"F-A-B," said Kerry. "By the way, I'm still having trouble trying to pin-point Heidi's location except that it's in the same area that the plane crashed."

"If that's the case, then why can't they find her?" asked Gordon.

"Avalanche, perhaps?" suggested Leanna.

The others shivered.

"Let's hope not, but let's not rule anything out yet," said Daniel.

"Why shouldn't we try to contact her?" asked Katie.

"Good idea," said Daniel. "I'll give it a go." He changed radio frequencies. "Thunderbird 2 calling Heidi Rowley. Do you read me? Over."

There was no reply. This made everyone nervous. They normally didn't get this feeling whilst on missions, but this time was different. one of their own colleagues was in trouble, and they really didn't want to lose Heidi.

"Hold on, Heidi, we're coming," Daniel said quietly to himself.

The Swiss Emergency Services had managed to find the two band members who had jumped out of the heli-plane when it was falling and had reunited them with the rest of the survivors. Now there were only two people unaccounted for as the other two missing were revealed to be the two pilots who were killed in the explosion.

"Where is Elle French?" asked the tour manager. "You have to find her!"

"Don't worry, sir, we will," said the Chief of Police. "My men are covering the whole area. They can't have got far."

Heidi and Elle weren't far away at all, but the avalanche had not only trapped them in the cave, it had also covered up any footprints that they'd made whilst running for cover. The search teams wouldn't even suspect that there was a cave hidden under the huge pile of snow.

Despite the warmth of the fire, Elle was still shivering with fear. Heidi had come round to hug her to not only help warm her up but to comfort her too. Elle appreciated this but was still afraid.

"What's your favourite song?" Heidi asked trying to make conversation.

Elle blinked, surprised by the question. "Oh, er, i've got loads," she said. "The one I finish with is my all-time favourite though. Why do you ask?"

"Just wondered," said Heidi. "I thought maybe we could have a little sing to keep our spirits up?"

Elle pondered. "Actually, that's not a bad idea," she agreed. "What did you have in mind?"

Heidi had taken out her mobile phone. It didn't have any signal to make calls, but the music player was still working somehow. "What about this one?" she asked showing the song title to Elle.

"Eye of the Tiger?" said Elle, suddenly looking more cheerful. "Now, THAT'S a fun song!"

Heidi grinned and pressed the 'play' button. First the music began to play and when the right moment came, they began to sing.

"Rising up, back on the street

Did my time, took my chances

Went the distance, now I'm back on my feet

Just a man and his will to survive.

So many time it happens too fast

You trade your passion for glory

Don't lose your grip on the dreams of the past

You must fight just to keep them alive.

It's the Eye of the Tiger

It's the thrill of the fight

Rising up to the challenge of our rival

And the last known survivor

Stalks his prey in the night

And he's watchin' us all with the Eyeee of the Tiger!"

Kerry frowned. "Who's playing music?" she asked.

John, Katrina, Kaylee, Becky and Kelly looked around, puzzled.

"None of us are," said Kelly.

"Then why can I hear singing?" asked Kerry.

"It appears to be coming from one of the radio frequencies you're monitoring," said John. He moved forwards and fiddled with the holographic controls. "There! Got it!" he said. "Whoa - it's coming from the mountains close to the crash site!"

Kerry looked closely at the frequency. She blinked in astonishment. "That's the frequency from Heidi's watch!" she exclaimed. "Thunderbird 2, tune your radio to Heidi's watch frequency now!"

"We've been trying to call her without success, Thunderbird 5," Daniel replied. "Adjusting the frequency now."

What they then heard took them all by surprise.

"Face to face, out in the heat

Hanging tough, staying hungry

They stack the odds still we take to the street

For the kill with the skill to survive.

It's the Eye of the Tiger, it's the thrill of the fight

Rising up to the challenge of our rival

And the last known survivor stalks his prey in the night

And he's watchin' us all with the Eyeee of the Tiger!"

"Is…is that Heidi?" asked Wizzy.

"Who's the other voice?" asked Cassidy. "Sounds like there's two people singing."

"Thunderbird 5, can you pinpoint where that is coming from?" asked Daniel.

"Already done," said John. "It's about three-hundred yards away from where the plane crashed, and yet the search team don't seem to have found them."

"Scan the mountain," said Daniel. "Maybe there's a cave they don't know about."

Kerry used Thunderbird 5's scanners to make a holographic map of the mountain. "Good call, Daniel," she said. "There is a cave running deep inside the mountain, and there are two life signatures inside!"

"One obviously Heidi," said Leanna. "But who could the other one be?"

"Elle French I'd guess," said Katie.

"And we have a bingo!" said John. "I've run a voice-print analysis of the two voices. It's them! Heidi and Elle French!"