"Harriet Stevens to Artic base blog, I've been down here for two days now and my research is almost done." She smiled and looked around the cavern, "The quakes are still present, however, they're getting stronger."

The ice-cave shook again and Harriet ran from the truck as a large slab of ice fell from the ceiling, she got her breath back and slowed to a walk as she looked at the wrecked vehicle, the sighed to herself, "Great, no transport back. Oh well, I have to continue."

Meanwhile on the other side of the world, the Tracy family were having their own problems.

"Pleeease Scott?" Alan begged.

"For the last time Alan, no!" Scott groaned and from the looks of everyone else, this argument had been going on for a while.

"But why not? I wouldn't be a hassle."

"Alan, it's not that I don't want you with me, I just think you're too young to go to the mainland."

Alan pouted immediately, "That's so unfair! Even Gordon has been with you."

Gordon winked and Virgil hit him, "Don't start Gordon."

"Owww! You're so rough Virg."

Scott sighed, "Stop it guys. Listen Alan, I'm only looking out of you."

Alan sat down on the edge of the table and cupped his chin in his hands, "Fine, but I'm not going to forget this."

Virgil shook his head and turned back to a sketch he was working on, "You'll get your chance Ali."

Alan looked up to the celling, "Which is another way of saying never."

Back in Antarctica Harriet was nearing her destination, she gasped in awe at the entrance to the final cave and the crystals hanging from the cavern roof.

"Harriet's blog, I've found it. Final cave. It's beautiful and will open up hundreds of ideas for medical research," Suddenly the cave shook, "No, not now! Ahhhh!"

John called home, "International Rescue, we may have a situation."

Scott sat up straight, "Go ahead John, what's wrong."

"I've just caught a snippet of a scream about five minutes ago, location, Antarctica."

"A scream?" Gordon raised an eyebrow.

"I detected an earthquake around the caves there. Someone must be down there. Virgil, could you take Thunderbird 2 and aid?"

Virgil stood up and made his way over to the portrait, "FAB. Any specific vehicle I need to take?"

John smiled, "You might want to take the Pod Explorer, or The Spider as you call it."

Virgil smiled "FAB," And the portrait flipped back taking him down the chute to Thunderbird 2, Scott stood up and went over to the lamps.

"I'm going with him."

"But Scott?" John started.

"No questions John, I want to make sure he's going to be alright out there."

Both birds took off and headed off to the ice-caves of Antarctica, sheets of ice passed under them as they flew towards the Artic.

In the cave Harriet was in a bad way, a slab of ice had fallen on her ankle and she had felt it click slightly, now she sat against the icy wall in pain waiting for help after she had sent an emergency frequency to anyone near. The Birds landed and Virgil told Scott to wait whilst he accessed the cave.

"In what universe do you assess, and I wait?" Scott crossed his arms.

Virgil rolled his eyes, "I have the jaws, so?"

Scott smirked, "Alright fine. Be careful in there Virgil, ok?"

Virgil grinned then jumped into the Spider before driving into the cave leaving Scott in Thunderbird 1.

Harriet looked up to the sound of wheel tracks, then she saw the Spider came around the corner, it stopped a short distance away from her and Virgil got out, the ice-light glittered off his hair and Harriet took a quick gasp as he approached her.

"International Rescue, did you call for assistance?"

Harriet smiled up at him, "There was an ice-quake and I got trapped. The ice fell on my ankle."

Virgil knelt down and inspected the ice, "Wait here, I'll release the block."

Harriet sighed and watched him go back to the vehicle to retrieve the jaws, "What are those?"

Virgil smiled as he looked down at his 'help', "I call them the jaws of life, now how about we free your ankle?" He picked up the block effortlessly and she hissed slightly from the loss of weight leaving her ankle.

"Thank you so much," Harriet leant forwards to reach her foot but Virgil beat her to it, he ran a finger along the bone gently.

"You're welcome. I don't think it's broken but I'll help you back to my bird." Virgil extended his hand to her and Harriet took it shakily, "Here I've got you."

Harriet smiled slightly as she felt his arm come around her waist for support, "How did you find me, uh?"

Virgil looked at her, "It's Virgil. My brother picked up your scream from our space station."

"Well I'm glad you did. Umm Virgil, this is way too forward at this time, but when I screamed I was in the middle of discovering a rare crystal for medical research. Could you let me collect one before we head back, please?"

Virgil looked at the ceiling and then to the walk back to the Spider, "Miss?"

"Call me Harriet."

"Harriet, this cave is going to collapse if we don't move."

"I swear I'll be two seconds, I only need one, and the entrance is right here," She pleaded a little and Virgil gave in.

"Alright, but we have to hurry."

"Scott calling Virgil, what are you doing? John messaged me to say he predicts another quake in the next five minutes."

Virgil touched his comms link on his sash, "We'll be right out Scott, I promise, I have everything in hand."

"Who's Scott?" Harriet asked looking up.

"Who's that?" Scott enquired, his voice rising slightly.

"The girl I've just rescued. I'll be out soon Scott, step fretting."

Scott hung up his comms and growled to himself, "Well I guess I'm going to have to go and get him myself."

Harriet limped into the cavern and smiled up at the crystals before taking out a small chisel, "This one will do nicely."

"Need a hand?" Virgil smirked as she began to cut the rock away.

"Not at the moment, thank you," She tucked a strand of hair behind her ear and continued to cut, "Almost, there."

Virgil kicked the snow with his boot as he waited for her then he heard a small thump as the crystal landed at his feet, he picked it up and Harriet climbed down carefully, not wanting to put pressure on her ankle, she took the rock out of Virgil's hand and their fingers lingered on each other for a moment, then she smiled.

"Thanks, now we can go."

"I think that's a very good idea," Virgil lead the way and they headed out, suddenly there was a loud rumble causing the cavern to shake.

"An ice-quake, and stronger than before!" Harriet cried over the roar and cracking of ice.

"Let's go!" Virgil wrapped an arm around her to help her run then gasped, he looked up to see a slab of ice hurtling straight down towards him, Harriet dropped her crystal and pushed Virgil away to take the crush for him, "Harriet!"

Scott ducked for cover in the second pod vehicle as he waited for the quake to stop, then he called Virgil, "Virg, bro where are you? Pick up."

Virgil crawled back to where Harriet was coughing under the slab of ice, "Harriet, why did you do that?"

Harriet smiled, her lips glittered with blood and she swallowed painfully, "You didn't deserve to die."

"But neither do you."

"Shh," She pressed her finger to his lips, "There's nothing you can do, just take the crystal back to the research centre in Iceland for me, it can save lives."

Scott homed in on Virgil's signal and stomped down hard on the gas pedal, "Why don't you ever follow instructions Virgil?"

Virgil closed his eyes, "I've failed."

"No," She coughed and wiped away blood, "You haven't failed, I chose to save your life because I could, and this was my choice."

Virgil moved to lift the slab of ice off her chest, but her hand stopped him, "Please, at least let me free you?"

Harriet shook her head, "My body is broken, where would the relief be? No, just return safe to your brothers."

Scott spotted them and sighed before jumping out of the vehicle, in a few strides he reached Virgil.

"I'm sorry this happened Harriet." Virgil stroked her cheek and Scott's eyes widened.

"You still rescued me, and that's what counts. Now get out of here, the next quake will kill you too, save yourself," She whispered and squeezed Virgil's hand with her last ounces of energy, "Harriet Stevens, ice blog. This will be the last time you hear from me, the crystal has been delivered thanks to International Rescue. End recording."

"Goodbye Harriet, I won't forget the crystal, I promise." Tears came to Virgil's eyes and he leant down to kiss her.

Scott wiped his own tears away and gritted his teeth as his emotional barrier broke for his brother.

Harriet kissed him back with her last breath, "I always do crazy things, when I think I've fallen in love." Her limbs went loose and her breath vanished in a small wisp of vapour in the cave.

"Virgil, I am so sorry," Scott said quietly as Virgil stood up after picking up the crystal.

Virgil turned around and tears fell down his cheeks, "She rescued me Scott, and I let her die. Why did that happen?"

Scott wrapped his arms around his brother and stroked the back of his neck, "You did what you could Virg, and she chose to save you over love. I'm sorry that I can't make that sound any better."

Virgil nodded, "I wish I could've done something."

Scott sighed, "So did dad when mum died, but he had to let her go. Come on, we're not safe here. Virgil, come on," He tugged Virgil's arm gently and eventually his brother followed him to get a lift back to The Spider.

They eventually made it out and drove the vehicles back into the pod, Virgil got out and stood silently looking at the cave, Scott joined him and laid his hand on his shoulder.

"How do you mean, dad let her go?"

Scott followed Virgil's stare to the cave entrance, "He found mum in that avalanche, her lungs were full of freezing snow and ice, but he thought he could save her. Mum told him to leave her as there was no chance in saving her life. His promise was to look out for us, a promise I've taken from Dad to you guys."

Virgil turned his head to look at Scott, "He tried but failed?"

Scott nodded and sniffed slightly, "None of today's event is your fault Virgil, and you know that right?"

Virgil couldn't say anything, and finding Scott's hand, gripped it tightly, "I miss them so much."

"As do I," Scott sighed and rubbed his eyes on his suit sleeve, "Come on, let's deliver the crystal and go home."

The journey home was quiet and Virgil looked back at the cave as he flew, then at Harriet's blog recorder and the most important; the white crystal gleaming in the frosty light coming through the windows of Thunderbird 2, he sighed and with a soft voice sang quietly, "Beware the frozen heart."