Notes:

Thanks as always to my brilliant beta, Soleil_Lumiere.
This is a twisty one, folks... I hope you can trust me with it.

Chapter 1: Easy

Sometimes, it was pure.

This, just this.

Four tilting downwards, firing boosters that sent him and her plunging into a sea so bright-cut in its blueness that it made his eyes ache and his heart sing; water, deep but clear and with sunlight like swathes of silk cascading through it all.

Fish, thousands of them, shimmering and shining as he glided down between them, sea-jellies floating like forgotten confetti, and far to the left, a bronze whaler shark, sleek and effortless as it showed him how real gliding was done.

And to top it all off, someone to rescue. To help. Trapped, but not injured. Submerged, but not deep. Safe enough for now. A single rescue, a happy outcome, and nature doing its best to distract him by being as wantonly beautiful as complexity could ever be.

Okay, so John had space and a billion stars. Good for him. Gordon had a billion points of light in a single stretch of surf, and movement and life and surf-boys and girls besides. Scott had – well, Gordon would never know what Scott had that made him so Scott in his Scott-ness. Maybe nobility glowed like the underside of waves on a bright day like this, maybe certainty was as pretty as the tiny reef fishes disturbed by Four's nose as they flashed and glittered above Gordon's head.

All he knew was that this? This undulating, seductive world down below Virgil's skies and Alan's stars? This was pure, for him.

"I still don't know why they're using the old frequency like this."

Alan's voice, and that was pure, too. Pure grievance by way of resentment and petulant boredom. He'd wanted to come, just for the ride, but Scott pulled the homework clause and now Alan was stuck with Grandma, Kayo, Brains and Scott on Tracy Island, evidently bitching about the frequency used to call for help because it was better than bitching about International Rescue's commander – no doubt sitting somewhere close by.

"I don't know either, Alan, but let's just be grateful they got through." Scott had that finely calibrated level of sympathy in his voice that said, yeah, I'm sympathetic to the fact that you're here doing homework when you'd rather be out there rescuing people with your brothers, but yeah, you're doing homework so deal.

"It is odd, though." John, never afraid to run a slight anomaly into the wearied ground. "That's a frequency that hasn't been regularly used for years."

"Since your father's Mars mission, as a matter of fact. It's an interesting coincidence."

Brains. Ready with a hammer to finish off the anomaly if it showed any last signs of life once John was done with it.

"It doesn't matter about the frequency." Time for a little reminder of what they actually did here. Other than, you know, speculate each other into a coma. Gordon reached up to adjust the diving angle slightly, bringing Four to a cruising level. "The only thing that matters is EOS picked it up when no one else would have. Aaand – I'm coming up on the coordinates. Forty metres viz, lookin' sharp."

"Tell me it's merpeople."

That was Alan again, manfully aiming for the maximum distraction points in the commentary. His kid brother was flying a distress flag here. Must be history. Or economics.

Gordon wouldn't let him down.

"You know, now that you mention it – what was that stuff Lemaire sent you, Scott?"

Alan jumped in before Scott could answer.

"You mean those pictures of the sculptures they found in Yucatan? Those ones that looked like people with fish tails?"

"Yeah. Yeah. I dunno, Al – it looks like I'm maybe seeing…"

"Uh, Gordon." Uh, Virgil. Virgil the killjoy extraordinaire, currently hovering somewhere overhead in the Jolly Green Giant. "A little focus here?"

"Yeah, yeah." Sorry, Al, you're on your own fighting the homework monster. "Okay, I'm at the coordinates. And I can see - huh."

At 30 meters depth and in these perfect conditions, Gordon could follow the seabed spread out before him with the kind of clarity he rarely got to enjoy in rescue mode. A long reef banked around in a haphazard crescent beneath his feet, with rocky outcrops covered in coral, and green, brown and red algae, waving in the gentle current.

"'Huh?' That's it?" Virgil may as well have sighed it. "Any chance of a more accurate report there, Four?"

"Well, sure. If I had anything to report. Are you sure this is the right spot, Thunderbird Five? I'm not seeing anything."

"Let me just check again." From four hundred and eighty kilometres above, John ran the search algorithm once more. "Affirmative, Thunderbird Four. You should be right on top of it."

"Well, there's no welcome mat." He tried, but failed, to hide the frisson of pleasure as he added, "Guess I'm going EVA to find this underwater facility."

"John, was there any other clues about what we're looking for?" It was obvious from Virgil's tone that he was not best pleased. "Like what kind of an underwater lab?"

"That was the only description given." There was a clear frown in John's voice. "A woman, who said there were two of them trapped in an old underwater laboratory, at these coordinates. See what you can find, Gordon, but don't take too long. Given the weird frequency and the lack of identifiers, I'm starting to get a bit of a hinky feeling about this one."

"FAB." Gordon strapped on a rescue pack, dropped out through the hatch, brought his body out of Four's underbelly into a tucked spin then straightened out to release the energy in a smooth glide forward. It was close enough that he didn't use the EVA motor. "Oh, okay - I can see debris under the algae. There's been something here, at some point. Lemme just get at some of this growth…"

He carefully pulled aside the heavy fronds of the largest clumps of algae, and found himself nodding.

"Yeah, I think this is it. There's metal here, under all the overgrowth. I just gotta find an entrance. Have they been back in contact, John?"

"No. Not since the last transmission, about an hour ago. And I haven't been able to raise them, since."

An eyestripe surgeonfish came up to Gordon as he probed along the outcrop, swerving to grab at particles disturbed by his actions. He couldn't help laugh as it darted in at his fingers, a shimmer of silvery blue and yellow that seemed to have no fear of him.

"Hey, no, you're welcome. I'm your friendly food distributing service, brought to you by International Rescue and the letter G."

"You getting anything, Gordon, or is the whole rescue thing getting in the way of the fish petting?"

"I'd love to be doing the rescue stuff, Virgil, but I'm not finding a way in he - oh, wait, no. Take that back. Think I've just found the airlock."

It was horizontal and hidden beneath a spectacular coralline growth of lime green encrusted to the metallic hull that formed what Gordon assumed was the ceiling of the lab. Quickly he grabbed the airlock wheel and turned it, feeling resistance but far less than he would expect in a structure of this apparent age. That fact alone told him someone had been through recently.

"Entering now," he said, and registered Virgil's acknowledgement even as he reversed his actions of leaving Four to swing his body through the narrow opening and secure the outer door behind him. An old-fashioned airlock valve was before him; he worked it to the side and the water drained noisily from the chamber, leaving him standing in front of a rusted and salt addled door. He gripped the second airlock wheel and turned it to open the door and enter the facility.

A modern arc-light was suspended directly ahead of him, alongside the kind of light fitting he had not seen in real life before – something heavy, metallic and thick-glassed that made him immediately think of Jules Verne and guys in bulbous diving suits. Directly beneath that was a locker bearing typewritten tabs on discoloured paper, and to the left was a wall of gauges, all silent and still, with acid forming discoloured white and green crystalline eruptions from between the glass and the pipes leading into each.

"Wow, Virgil, this is old school."

"How old?"

"I dunno. There's equipment here, instruments that look like stuff from the 20th century. I mean, mid twentieth. Fifties, sixties, that kinda thing."

"Huh." Virgil sounded interested, the dork.

"No sign of our couple. Going into the next room now, if I can open this door. It's individually dogged, got some kind of anti-corrosion surface." He noticed the gleam of the hinges. "Looks like it's been lubricated recently."

He turned the handle, and stepped into brightness.

"Oh! Am I glad to see you!" A man, stocky and young, stood up from where he was kneeling beside a woman, sitting propped against the wall with a jacket spread over her body, her eyes closed. "Are you International Rescue?"

"Yes, I am. Part of it. Gordon, and I'm here to get you to safety." He moved to swiftly take the position the young man had just vacated, reaching for the woman's wrist to check her pulse. "Hello? Ma'am? Are you injured?"

The woman opened her eyes, briefly, and moistened her lips but didn't speak.

"She's sick." The man clenched his fists, helplessly. "It's this place. I think there might be some kind of toxin in the atmosphere."

He was wearing a wetsuit, as was the woman, but not using a breathing apparatus. Gordon asked the question with a look.

"Our diving equipment malfunctioned. The valves aren't working, or something. Jennifer knows better than I do, I just know we can't use them." He gestured to where their tanks were piled unceremoniously together beside the wall.

"Okay. Won't be a problem. I'll take you across one at a time to my sub, take you to the surface."

"But…" The man bit his lip, then continued, "I know you gotta get us out of here, but you have to find the others!"

Gordon paused in his appraisal of the woman's vital signs to glance back up at him.

"Others? We thought two…"

"There are others here. I'm sure there is. We heard voices, from down there – " He pointed to the end of the room and a further door, partly shadowed by the overhead struts and equipment banks lining the walls.

"Down?"

"Yeah, it's quite extensive, this place. We heard them, that's why we called you, and then the tanks wouldn't work and we ended up needing rescuing too."

Gordon looked over his shoulder at the darkened door. It wasn't an appealing notion, heading downwards in a laboratory at least a hundred years old, but if there was the chance that someone else was here…

He touched the comm point on his sash.

"Thunderbird Five, you getting any other readings down here? Thunderbird Two?"

Two voices in the negative.

"But the signal I'm getting is inconsistent," John added. "There must be a hell of a lot of iron in the construction of that place. Your signal is unsteady. Could be that the deeper you go, the more disruption there is."

That wasn't a comforting thought, somehow.

"Okay. Virgil, I better dry tube these two and check out the rest of the facility, just to be sure."

"FAB, Gordon. Take it easy down there."

"Will do."

The man looked at him in confusion.

"What do you mean, 'dry tube'?"

Gordon smiled, a well-honed expression that spoke of nothing but corn-fed farm-boy sincerity.

"It's perfectly safe. It's a way of getting you both up to the surface quickly and securely as we can. I'll do a longer search down here while you're looked after on the main rescue plane."

"Oh." He seemed doubtful, but nodded.

"Alright. We'll be quick as we can. I'll come straight back for you. In the meantime… ma'am?" The woman fluttered her eyes open at him again. She had dark hair and glasses and the kind of nondescript face that had Gordon wondering if he knew her. "Do you think you can walk with me to the airlock?"

"I'll try." She raised her arms and Gordon bent to scoop her up, supporting her weight against his hip. She clutched at his chest, then steadied.

"I need – can I take my bag?"

"Uh – sure." Bags and other personal possessions weren't usually part of a rescue plan, but with no great time pressure and plenty of room, Gordon didn't hesitate to bend his knees so that she could dip and lift up the large water sealed carry-bag.

"All my footage. And my notes," she explained, almost apologetically, and he grinned at her.

"Do not want to make you write all those again," he agreed. She smiled, but clung tightly to him still as they crossed to the door.

"How will – do I have to hold my breath for long? I'm not feeling very strong, I'm sorry."

"Hey, don't worry." He half-turned so that he was addressing both of them. "I've got full face re-breathers on me. My sub's only twenty feet away. They'll last long enough to get us safely on-board."

"Thank goodness!" the woman gave him an admiring smile. "I don't know what we would have done if you hadn't come down here."

It was common enough, that moment of heartfelt gratitude offered to a rescuer, when the possibility of death had begun to freeze a person's soul and the rescuer appeared as an angel of mercy in their torment. Never something to be taken seriously; all God complexes would be neatly parked at the door, thank you and goodnight. The temptation to dive into those eyes full of relief and worship was one long dismissed by each of the Tracy boys. They knew real heroism, and though each one would assign it to the other family members, none of them would claim it for themselves. From the inside, heroism looked a lot like kindness and compulsion, a case of just not being able to do anything else, and that, as Lee Taylor would say, didn't pin no prizes on no mule.

But Gordon felt something as she gazed up at him, and not what he expected.

Brief awkwardness, sure. Momentary embarrassment, maybe. But not this.

Not this.

This was a long, slow, ice-cold roll of revulsion.

It surprised him so much that for a long moment he looked down at her with his mouth open, eyes wide. She blinked at him.

"What is it?"

Bigger embarrassment, now, as he quickly opened the door and brought them through it, covering his momentary lapse with plenty of movement and little eye contact.

"Sorry – just thinking through logistics." Barefaced lie, but hey, it wasn't the first time he'd flannelled a bit in saviour mode.

But that slow wave of coldness persisted, and if he could lie to her, he couldn't kid himself for long.

This woman was making every atom of his squid sense flail a tentacle of alarm in his face. And he just could not for the life of him see why.

She was the most ordinary of ordinary women. Someone you would pass by in a street and never notice. Someone in a corner of a room you'd never register as present.

"Hey, do I – " He hesitated, feeling foolish, but something urged him on. "Do I know you? Have we met?"

The woman looked genuinely startled.

"Goodness. I don't think so?" She gave a self-conscious chuckle, even as she sagged a little more in his hold. "You might not remember me, but I'd certainly remember you."

"Yeah. Sorry. I don't know why I – sorry. Let's just get you on the surface, hey?" Embarrassed and confused, he unpacked the re-breather and checked that it was working before carefully putting it over her face.

"Breathe normally, just in and out," he said, and she followed his instructions, looking less wan almost immediately. "That's great. Okay, we're getting in the airlock now – there you go – and I'll be letting in the water. It sounds kinda noisy, but that's just 'cos it's old. Gets a few creaks in its bones at its age."

She smiled, under the rebreather, and he opened the valve to the sea before turning the airlock and bringing them back up and out, into the brilliant underwater garden that hid the lab.

It occurred to him, an odd, sudden thought, that neither of the couple had said a word of goodbye or good luck to the other as they parted. Not completely unknown; in the moment, when survival was the priority, niceties got lost.

Still.

That slow cold wave rolled through him again, even as he opened the rear access to Four and brought the woman inside it.

She stumbled as they cleared the airlock, and he steadied her as he brought down the dry tube.

"I'll just help you up on here. Are you okay? Think you can lie down here for me?"

"It's going to close me in?" She grabbed tight to him again, and he nodded, smiling with as much reassurance as he could manage.

"Just for a short time. Straight to the surface. From down here? Less than a minute. Will you need de-pressurisation on the surface? There's a decompression tank ready if you've been deeper."

She shook her head, but as she did so, her legs gave way and she slid downwards to sit on the floor.

"Oh, I'm sorry. I just – could I have a drink of water, please? Before I go up? I'm so thirsty."

"Of course." He turned and reached up into the overhead lockers, pushing aside various items of equipment until he could bring back a re-usable water bottle and fill it from the desalinated water dispenser. "Here. Take slow sips. Rehydrate for a bit."

He tapped his sash again. "Virgil? First passenger for the dry tube is just about ready. Her name's Jennifer and she's looking forward to the first class service we promised in the brochure."

"Good news, Four. I'll be standing by to retrieve."

"FAB." He smiled down at her again, and it felt fake, and that felt mean. This poor woman had done nothing to be accosted by his heebie-jeebies. There was no possible reason for him to be regarding her as anything but a person in need of help. Wasn't her fault she got stuck in that creepy ass lab.

And at that thought, his mind cleared. Of course! It was the lab that had him freaking out. There was just something about it – the old style equipment and design, the darkened struts, the shadows, the closed door into hidden depths… There was something in the atmosphere more than toxin, and it tasted of desperation and abandonment and all the kind of tainted loneliness left behind by submariners lost to the land forever. The truth was that Gordon had a kind of sensitivity to atmosphere he tried his damnedest to keep hidden from his brothers; successfully he told himself, poorly he suspected.

"Feel better?" he asked, and she smiled, wearily, and handed the bottle back to him.

"Yes. I just need to get into the sunlight. That place…"

"Ha! Yeah, I hear you. Nightmares for days. Okay, well, if you just hop up here – that's it," as he bent and hefted her onto the dry tube bed. She patted it nervously, looking about herself, before allowing him to gently push her back to lie in its harness, still clutching her bag. He strapped her in, and gave her a friendly nod.

"You'll be fine. I promise."

"Thank you," she said, and then he hit the button that folded the dry-tube up and shot her out into the water on an upward trajectory to his brother, waiting in the module on the surface above.

He took a moment – several moments - to check his gear, tap the rescue pack with the extra re-breather and readjust his sash, before heading down and out again, back to the hidden laboratory under the reef. He told himself he was being the normal, meticulous professional he always was, that any suggestion he was actually reluctant to go back into that abandoned place was vile slander, and that whatever part of his subconscious was suggesting it could just shut the hell up and cut it the hell out.

"First dry tube away. Heading back to the lab for the second rescuee."

"Copy that, Gordon. I have a visual on the tube."

Well, one safely up top, one more to go. A slide, a flip, and he was back in the water, heading for the obscured airlock.

It seemed darker somehow, as he re-entered it. The arc-light was dimmer. He frowned at it, surprised to find the hairs on the back of his neck were up.

Ghosts were John's thing, not his. This was ridiculous.

But it didn't surprise him to find the man was waiting for him by the door as he came through, and almost leapt at him.

"I heard them. I swear to god, I heard them!" The man went to grab him, and then got control of himself. "There's someone calling for help down there. Definitely. Sounded young, too."

Any chance Gordon had of hand-waving a further search disappeared with that. The man, at least, was convinced and convincing, although Gordon glanced up and around at the dilapidated state of the facility and grimaced. No one would stay down here for long by choice. Maybe some other foolhardy adventurers, trapped here by ill-fortune in the last day or so?

"How long have you been here?"

The man paused in his feverish packing, frowning. "What difference does that make?"

"I'm trying to figure this out, how someone else could be down here without anyone knowing about it."

A shake of the head. "We only got here this morning. I don't know how the hell they got in here or when, but there's someone here, no doubt about that."

Gordon found himself straining to hear something coming from below them, some indication that there was anything but stale air and lost history down here, but he heard nothing. The man caught at his arm.

"Maybe you should go look while I wait?"

That got Gordon's attention. He could tell the guy was anxious to leave, and he didn't blame him one bit – but here he was, offering to stay waiting alone while Gordon checked it out. It was a generous offer, and a brave one, and the smile Gordon gave him was genuine.

"No. We'll get you to safety first. No point in both of us - " he almost said, 'being put in danger', but changed it to, "hanging around here. I'll get you up with your partner, then I'll take a look."

"Okay. If you're sure." By the way the man was scrabbling together the last of his equipment and bundling it into his bag, he didn't need much persuading. He held it up at last, a tentative grin.

"Room for all this on Four?"

Gordon chuckled.

"You bet. Come on. Let's get you out of here."

The trip was as non-eventful as the first, and Gordon helped the man and his bag onto the dry tube with the thankful sense that the first and most important part of his job was done.

"Thunderbird Two, we have the second dry tube ready to go. I'll be taking another quick look in the lab, though – both of our guests heard noises down below, so I'll check that out just to be sure there's no one else."

"Are you sure that's necessary, Gordon? I'm not picking up any other life signals."

"Yeah, I know, but they're adamant and - I just wouldn't feel right if I didn't, you know? I'll take the air quality meter to test what's what."

He could hear Virgil sigh this time.

"Yes, I know. Okay. But be careful? Check back in within twenty, or I'm rigging the pod and coming down after you. Don't think I won't."

"Aw, you'd really get your toesies wet?"

"You better believe it."

"FAB." Chuckling, Gordon signed off, then wiped his sweaty palms against his thighs.

Time to go and be an adventurer. Trouble is, all the adventurers he knew, like Elly and Buddy, and even the Lemaires, tended to go in pairs. Much more fun if he had Alan, sans homework, down here with him.

He put that aside. It was highly unlikely anyone was really waiting for rescue in the depths of the laboratory – far more possible that it was a shared hysteria due to being trapped in a creepy ass lab, or that some kind of leak in the system had poisoned the air enough to produce hallucinations. With his own IR uniform, gloves and breathing apparatus, he would be immune to anything in the atmosphere beyond what his own treacherous imagination could conjure for him.

He gave an unhappy sigh to rival Virgil's, and headed back over to the reef.

Only this time, he brought the biggest flashlight he could find.