A/N: The other name for this chapter is 'Divine Intervention'. I've been typing it all week, so it's a bit all over the place. Never in my life have I been so needed to aid with school projects, French lessons, and family birthday parties. And I swear, if I have to answer the phone one more time today, I'm going to start sending people anthrax in the mail. Hope y'all enjoy it, anyway.

xxx xxx

Rose was swimming as soon as she hit the water.

The warmth of the lake shocked her more than icy cold would have. The Doctor splashed down next to her, and Rose kicked hard against the solid side of the nest. Spluttering, with the brackish water surging to over her, she threw arm over arm in an awkward free style. She felt heavy and uncomfortable in water, even though she'd discarded her snow jacket before diving in. Swimming lessons did nothing if you didn't visit the pool every so often, and Rose hadn't been in years.

"Keep you chin up."

Beside her, the Doctor moved easily through the water. His face and hair shone gold in the early morning light.

"Easy for you to say!" Rose panted.

Water poured into her mouth. Rose coughed, and spat it out quickly. It had a foul, acrid taste, like rotten eggs. She clamped her mouth shut, and continued towards the shore.

The Doctor rolled like a seal in the water. The warmth soothed the pain in his ribs and shoulder. Lying on his back, with one eye on Rose as she floundered beside him, he could see that the halo of fog was descending rapidly.

If he was right about Beta, then hydrogen sulphide wouldn't be the only poisonous fog pouring down the slopes towards the lake. Hydrogen chloride and sulpher dioxide would burn their eyes and throat, and any hydrogen fluoride could prove fatal.

But as deadly as they all were, the Doctor wasn't particularly worried about them. Nor was he bothered by the slick, unseen bodies that passed through the water beneath him. The glimpses of black flesh and bleached bone that slithered just under the surface did nothing to perturb him.

"How long can you hold your breath, Rose?" he wondered aloud.

Rose gagged on another mouthful of black water before replying. "Two or three minutes? W-we don't have to go underwater, do we?"

"I hope not. We'll be dead if we do." The Doctor said, grinning.

He rolled back onto his belly, slowing his pace to stay beside Rose. The lake's edge was twenty yards away. Five yards from the shore, white water poured into the empty air. Droplets sprayed up as unseen feet trampled the surface. Light shadows freckled the muddy shore before the snow line.

The golden globe of the sun crested the mountain tops. The fog halo hovered thirty feet about the lake surface.

"Not long now, Rose," the Doctor said, seeing his companion beginning to slow, "Don't stop."

Thirty feet wasn't much. Like a pilot fish, the halo of hydrogen sulphide was a good indicator of the other gases around. But hydrogen sulphide was a light gas, only slightly heavier than warm air. The heavy gases, the invisible killers, would reach them far before the halo touched the lake.

The invisible killers. Carbon monoxide and dioxide. Odourless, colourless, lethal. The initial symptoms were dizziness and a feeling of weakness, and very soon after, suffocation. In the warmth of the rising sun, these gases would be pouring down the slopes, seething out of every crevice and fissure, pooling in craters, but always moving down, down, to the lowest point in the land.

Right now, that point was the lake.

"You can touch the bottom here!" the Doctor exclaimed, his foot brushing the muddy lake bed, "We're almost there!"

Rose struggled forwards. She was trying hard to quell her panic: all around her, there were flashes of taught black muscle and glistening bone. Spiky crests of backbone cut through the water, occasionally preceded by a white dome of knotted skull.

Nearer to shore, the creatures rose out of the water on their thick hind legs, sheeting white spray from their hunchbacked bodies as they lumbered onto solid ground.

"This is mad!" Rose shouted, scrambling towards the shore on all fours, "We'll be eaten alive!"

"Just run!" the Doctor yelled back, ignoring the creatures that crashed up out of the water around him.

The dawn sky was lighter now that the sun was wedging itself by degrees over the mountain tops. Behind them, the halo was only fifteen feet from the lake surface.

Rose pulled herself up, out of the water. She didn't notice the leeches clinging to her arms and neck. One of the creatures, running blind in its desperation to escape the lake, shoved her aside.

"Gotcha." The Doctor said, catching Rose before she slipped on the oozing mud.

Side by side, they raced up the shore line, and into the snow. Rose had no idea of what they were running from. It seemed to her that the biggest threat to their survival was running right beside them, in the form of the creatures.

"Can't we stop?" she gasped, trying hard to keep up with the Doctor.

The snow was fresh, and deeper than the day before. Rose sunk knee-deep into the unmarred drifts. She barely recognised the slope as the one she'd so carelessly tobogganed on the day before.

"If you want to suffocate, yes." The Doctor panted. His whole body felt red-hot. If he hadn't had Rose behind him, depending on him, he would have laid down and died.

And regenerated again, no doubt. But Rose was there, and she was depending on him, and she couldn't regenerate. With a guttural roar, the Doctor forced himself onwards.

Streaming around them, like water flowing around a boulder, the creatures ran. Tens and tens of them, sprinting on their huge webbed feet, as agile and spry as antelope. They didn't throw so much as a sideways glance at the two time travellers.

"When I say so," the Doctor's breath came as a sharp hiss, "Hold your breath. For as long as you can. Got it?"

Rose didn't get it. The creatures that had been so eager to rip them apart the day before were completely disregarding them today. What were they all so panicked about? And why on earth would she need to hold her breath?

"Got it." She agreed anyway, scampering on her hands and feet to keep pace with him.

The Doctor grunted in reply. His attention was almost entirely devoted to watching the creatures ahead of them. The snow a dozen yards in front appeared to be empty, though it wavered as though distorted by a great heat. As soon as the creatures reached this constantly retreating wave of heat, they disappeared. Vanished. Like they'd stepped into a shimmering portal.

Suddenly, there was a metallic shriek from one of the creatures before them. Its huge head convulsed, and the creature toppled over, crashing to the snow.

The Doctor stared at it for a split second before shouting, "Rose! Now!"

By now, half a dozen of the creatures were screaming. One by one, they collapsed. A few struggled pathetically to get up. Others didn't move at all.

"What?" Rose cried, over the screams.

"Hold your breath!" the Doctor shouted. It was useless. She'd never here him over all the commotion.

Almost angrily, he spun on his heel, and grabbed a handful of Rose's hair. He forced her down, so her face was mere inches above the snow. She stared at him with wide, terrified eyes.

"Hold your breath!" the Doctor snarled, waiting until she did so before he hauled her back to her feet.

He released her hair, and took her by the hand instead. A nauseating wave of cold, heavy air washed over them. The Doctor felt his stomach lurch, and his ears popped with the sudden change in pressure.

Rose's lungs burned. Her head felt strange, reminiscent of the night before. She let the Doctor drag her up the mountain side. It felt as though all her energy was being sucked out of her. Greasy grey sparks floated across her vision.

"Rose, Rose."

The sound of her name being called seemed to come from a long way away. Rose opened her eyes, though she didn't remember shutting them.

"You can breath now."

Rose stared up at the jagged thrust of rock beside her. Dimly, she recognised it as part of the outcrop that had halted her toboggan ride the day before.

"What's going on here?" Rose said, when she could manage the words, "This is nothing like you said it would be."

The Doctor sat down next to her. He grinned, but the expression was humourless.

"It shouldn't be like this," he said, "Beta is a dead planet. Though," he grinned again, "I suppose it all depends on what you define 'dead' as."

Rose was feeling better now, stronger. The cool press of snow against her skin was refreshing.

"I wouldn't call monsters springing up all over the bleedin' place dead." she said.

"Freak event, that." The Doctor replied, closing his eyes, "An incidental patch of intense heat allows life to flourish. Happens all the time."

"Bloody vicious life." Rose said. She leant back against the tall black rock, and looked back down the slope, towards the lake.

Once again, the landscape was empty. Utterly devoid of life. A sudden thought struck Rose as odd.

"Those creatures are really frightnin', aren't they?" she frowned, "And sort of…smart. Like yesterday, when they were chasing us, they seem to sort of, you know. Know what they were doing."

The Doctor lolled his head towards her. "They'd have to be smart to survive here, I s'pose."

"Yeah, but it's not like there's any humans here, is it? Like you said, we're in the prehistoric era. Humans don't even exist yet, do they?"

The Doctor shook his head, no. His eyes were still shut, and he appeared to be dozing off. Rose punched him lightly in the arm before continuing.

"Hey, if I have to listen to you rambling, you should at least hear me out." She told him, laughing, "What I'm tryin' to say is, if those creatures have never seen humans before, how come they knew what they were doing with us?"

"Well, I suppose it's because… it's probably due to… maybe it's…" the Doctor blinked, then stared at Rose, "That's a good point, actually."

Rose grinned, "Thanks. Hey, what are they, anyway? I've never seen anything like them."

"It's hard to say." The Doctor said. He was frowning slightly, and had that faraway look in his eyes, like he was distracted by some perturbing thought, "What I've seen of their dental and anatomical structure, they're almost certainly amphibious."

"What, they're frogs?" Rose couldn't help but laugh. The thought of being hunted by giant frogs was just too ridiculous.

"I'd say caudata. Salamanders. There's more to them then we can see, you know. They're covered in a layer of transparent skin, for one. They have three rows of serrated teeth on their top jaws, and only one row on the bottom, a classic sign of amphibia. That, and the presence of protruding gills and a tail, indicates," the Doctor glanced at Rose, and shrugged, "That they're salamanders."

Rose thought about this. "I had an axolotl once." She said, "And I know they're salamanders. But it never once got out of its tank and tried to eat me."

"Did you know all amphibians swallow their food whole?" the Doctor wondered, knowing full-well that she didn't, "All those scary teeth are used for nothing more than trapping prey in its mouth. They gulp it down, and it gets digested in their stomachs."

"So what?"

"So, did you notice the size of their necks? There's no way they could swallow something as big as you."

"Uh-huh. And I'm big, am I?" Rose queried, glowering

"No!" the Doctor said hurriedly, "Not at all. I just meant that uh, they couldn't eat anything nearly as large as a human. Any human, not just you. Couldn't eat big old me, either, ey?" he gave a fake laugh, "You know, I bet the biggest things they eat aren't any larger than a football."

Rose was still glaring at him when her stomach growled onerously.

"I see all this talk of food is making you hungry." The Doctor said. He too was feeling better for the rest, and dreading the walk back to the alcove. Especially if Rose was right, and the TARDIS was missing. He had no idea of what they would do, then.

"I haven't eaten for a day and a half," Rose said hotly, "I didn't get a chance to have breakfast yesterday, you know."

"You ought to have brought something with you. I always do."

"Well, sorry I didn't prepare for a bloody safari!" Rose snapped, rising to her feet. She was always irascible when she missed a meal, "What did you bring, anyway? A flippin' banana?"

After one last withering glare at the Doctor, Rose stormed off up the slope. The Doctor stared after her in wonder.

"Rose!" he shouted at last, when it was apparent she wasn't coming back.

She didn't reply. The Doctor climbed awkwardly to his feet.

"Rose!" he shouted again, trudging after her.

This time, Rose paused. She didn't say anything, and kept her back to him, but he took it to mean that she would wait for him to catch up.

When he was only a few feet behind her, Rose said, "We have no food."

Her voice was low, and forcibly calm. The Doctor would have preferred her yelling at him.

"We have no shelter." Rose continued, "And no way off this planet."

"We don't know that for sure. Maybe you just overlooked the TARDIS last night. It's a big mountain. Easy enough to miss a little thing like the TARDIS."

"The only reason I overlooked it is because it's gone." Rose scowled, still not looking at the Doctor, "And what's more, whatever you say otherwise, those creatures were hunting us yesterday."

"Maybe. But not for food." The Doctor said. Rose was back to stomping up the mountain slope, and he was struggling to keep up.

"I suppose they wanted a play date." Rose said dryly.

"Arguing isn't going to make things any easier, you know."

Rose was silent. Her shoulders were hunched and stiff. She was no less angry for the lack of quarrelling.

"I get it." The Doctor said after a while, feeling he needed to say something, "You're hungry, and muddy, and cold. And you were covered in leeches-"

"Leeches!" Rose shrieked, cutting him off, "What leeches?"

"The, um," the Doctor looked at her dumbly, "Uh, they uh, dropped off you when we went through the em, carbon monoxide."

"Why didn't you tell me there were leeches on me?" Rose cried.

"I didn't uh, think it was a good time to mention it."

She stared at him, mouth agape. She made several attempts to speak, then gave up and shrugged helplessly.

"You're bloody unbelievable." Rose said at last, voice faint.

"Thanks." the Doctor grinned.

By some unspoken agreement, they were both headed for the alcove. Rose was silent as she led the way. She was in no mood to talk. The Doctor trailed a short way behind her, doing his best to keep pace. There was a lot of things about Beta that bugged him, a lot of things he didn't like, but they were all things he could explain.

And then there was something else, something bigger. Something he couldn't quite put his finger on. He was also experiencing the unfamiliar feeling that Rose was right.

"Well, here we are."

He glanced up at the sound of her voice.

"That was quick." The Doctor commented. He was actually a little surprised at how fast they'd reached the alcove.

The sight of the small, sheltered bay was unmistakable. As it had been the day before, when they'd first stepped out of the TARDIS, the snow was perfect and untouched. It glittered in the morning light.

"You see? It's gone. I didn't overlook it at all." Rose said, smiling smugly.

"I wonder where she's gotten to." The Doctor mused, stroking his imaginary beard.

He took a step closer to the edge of the alcove, and peered down at the ravine. The rock wall wasn't quite as sheer there, and the horizontal crests of rock were closer together. If he squinted, it almost looked like stairs…

"Do you see something down there?" Rose wondered, inching closer to the Doctor. As anxious as she was for any sign of the TARDIS, she was sure to keep him between herself and the edge of the cliff.

"Um, Rose?"

The Doctor turned away from the ravine, and looked at Rose. At least, she thought he was looking at her. Or was there something else…?

"What?"

"Would you mind turning around?"

With the fluid motion of one who had done so many times before, the Doctor raised his hands above his head. Rose was now certain he wasn't looking at her.

Slowly, frowning, she repeated his movements.

"Oh," Rose raised her eyebrows, "What are Slitheens doing here?"

xxx xxx

Yes, I know. Bad ending. It's not really as bad as it sounds, I promise.
Oh yeah, and if you've never done shots of Jagermeister, don't start now. The only thing I remember about Doctor Who on Saturday is that Rose was a dog. Or something. And saying, "I love you the Doctor."

Sorry this took so long to put up! If my bf isn't fired, the next chapter will be up tomorrow or Thursday. Otherwise I'm hand-holding.

Cheers.