A/N Thank you for all of those leaving reviews -although I'd like to thank you individually, it's not going to be possible at the moment. Off to London for a few days now as I'm in charge of the marking of an AS exam. Will try to keep updates coming!

Chapter 37

The stream disappeared into the hillside with no sign of a gap big enough for a rabbit, never mind a human to get through. They split up, searching around the undergrowth in the dim light looking for the entrance that should have been there. Eventually, Jack saw evidence of a recent landslip, a tumbled heap of bare rocks, not yet covered in moss and lichens, covering the base of the hill near to where the sound of water could be heard trickling underneath. They'd have to shift them first before they could gain access to the caves.

Between the four of them they managed to roll the boulders out of the way. The exertions causing them all to warm up, not a bad thing in itself, thought Jack, although sweating would only make them cool down faster once underground.

The gap was low down, requiring them to lie flat on their stomachs in order to crawl through. They took it in turns to shove their back packs in front of them as they wriggled through the gap into the cave beyond, pushing themselves forward gradually, their feet slipping on the wet stone floor. They couldn't use their torches until they had made their way through the narrow opening; it was less than two foot high and they had to crawl for at least ten feet before there was room enough to get up on their hands and knees. Ianto felt his pulse rate increase as the rocks seem to close in around him. He stopped, unable to hear Gwen's shoes scraping on the ground in front of him, he panicked for a while, not sure which way to move, terrified that he'd gone in the wrong direction. Then a bright white light dazzled him.

Cautiously standing up in the area beyond the crack in the rocks, Gwen had put her torch on first and was shining it in Ianto's direction, encouraging him towards her. He scrambled through rapidly, grateful to see that he wasn't lost and relieved that he was no longer in the pitch dark.

Owen came through next, with Jack last. Shining their torches at each others' faces, it was clear that any residues of humour had been left outside in the daylight. Here the cold, damp air seemed to seep through their clothes, insidiously, chilling them to the bone. Owen checked his PDA and conferred with Jack before heading off in the direction indicated. They would use Tosh's modified GPS to navigate their way through to the larger of the caverns, where they were most likely to find stockpiled weapons.

Jack let Owen take the lead, followed by Gwen and then Ianto. He stayed back, keeping watch on Ianto, ready to step in if necessary. Although they all looked pale and gaunt in the glow of the narrow beamed torches, Ianto had looked particularly troubled and Jack understood why.

The roof was still low enough that Jack and Ianto had to duck their heads in places, avoiding thin, pipe-like stalactites that loomed out of nowhere. This meant that they didn't see Owen and Gwen stop suddenly and walked straight into them. They had reached the set of caverns indicated on the 3-D plan of the cave system. The torch beams no longer bounced off walls close to them on all sides, but stretched out to be swallowed up in the darkness. Jack slipped his back pack off of his shoulders and drew out a larger torch that he handed to Ianto, then he reached in to extract the heat sensor that Tosh had asked Rhys to get to him.

Jack moved in front to scan the area for any heat signals. There was one anomaly, although not emitting sufficient heat to be a mammal, it appeared to be too large to belong to any other creature they may have found living in the caves. He frowned, but was satisfied that there were no guards lying in wait. Then he took the lamp from Ianto and switched it on, this time fully illuminating the caverns.

Gwen gasped, seeing the extent to which the caverns went into the hillside. There were signs of the blasting that had been carried out to enlarge the area, as well as a number of steel props holding up the walls in places. This was definitely a storage area, there were stacks of metal crates of various sizes and dimensions in neat rows along the side walls. Jack shone the lamp upwards seeking out any sign of security cameras. There didn't appear to be any, but that didn't mean there weren't any.

"OK, this is what we do. Open the crates if you can, record the contents, take photos, measure for radiation levels – all types, alpha, beta, gamma and delta waves. Don't touch anything inside the crates and do not try to figure out what any of it is. We can do that once we get out of here. Gwen, you're with Owen – I want you two to work your way along the left hand side, Ianto and I will work our way down the right hand side of the cavern." He indicated the directions to make himself clear.

"We should leave anything we don't need to carry here so we can move faster," suggested Ianto, taking the recording device from his backpack and then pushing it into the crevice they'd just emerged from. Whilst the others agreed and set to taking what they needed from their own bags, Ianto slipped one gun into his pocket and another into the waistband of his jeans. He had a feeling they'd need to be well armed.

"Ordinary comms aren't going to work down here, so we need to stay together. Don't lose sight of each other – clear, Gwen?"

"Understood, Jack. You too, OK?"

"You can bet on it," Jack grimaced as he pulled back his coat sleeve to look at his watch. "Right then, we meet back here in half an hour, exactly."

They spread out, two going each side. One held the torch, whilst the other opened the crates and took readings of background radiation, thermal output and various other parameters.

They had reached to a point that was half way around the perimeter of the cavern when Gwen and Owen stooped beside a cage that appeared to be the source of the thermal output. Gwen reached out in awe as if drawn to the creature inside, her hands resting on the metal bars of the cage itself.

"Oh my God, Owen, look – it's a –"

"Well fuck me-"

"What's that sound?"

They leapt to their feet as they heard the distant sound of running footsteps – boots pounding along echoing chambers.

Jack and Ianto stopped where they were, on the opposite side of the cavern and looked to where Gwen and Owen stood, above the cage a motion sensor had been set up to monitor its occupant. It was now flashing red and had obviously tripped a security alert.

The sound of heavy soled boots splashing through wet puddles was getting closer, coming from the direction of a manmade tunnel close to where Jack and Ianto were standing. Ianto gave Jack a meaningful look and then cupping his head, quickly gave him a desperate kiss, the sort that tasted of 'goodbye'.

"I love you," he whispered urgently and then pressed the recorder into Jack's hands, before turning and sprinting away without looking back.

"Ianto!"

Ianto swallowed hard as he darted down the tunnel. There was nothing else for it – Ianto knew there had to be a decoy to allow time for the rest to escape. He figured the others would be able to move faster through the caves without him, and not only that, these guys wanted him for some reason or other, so they were less likely to kill him than Gwen or Jack.

Jack didn't have time to stop him – Ianto was going to sacrifice himself, the bloody idiot! He heard Owen and Gwen running back in the direction of the place they'd started from and he sprinted across the cavern towards them.

"Get out of fuck out of here –" He shouted as he threw his recorder across to Owen. "Don't wait for us! Get back to the Hub, get Tosh onto this and make sure UNIT get their asses down here."

Then he turned on his heel and ran after Ianto, cursing himself for having lost sight of him, something he'd sworn he wouldn't do again.

"Jack, what the fuck are you doing?"

"I'm going after Ianto!"