"Hold on! We can't just leave!" Donna struggled against the Doctor's vice-like grip on her arm as he pulled her toward the TARDIS. She glanced helplessly back at Alice who stood watching them in the rain, her arms tight around herself whether from cold or fear, it was hard to tell.

"The longer we stay in that house, the more at risk we put the family," the Doctor said.

"But the baby! What's happened? We have to..."

"We will! Come on!"

The wind was picking up quickly. Behind them, a door slammed as Alice returned into the house. As if the sound had awoken something, a gust shrieked past them, almost knocking Donna off balance. The raindrops were so large that they were almost painful on her skin.

"What's going on?"

"It's us! It's worse wherever we are," was all the Doctor said and she couldn't be sure she heard him properly against the wailing sound all around them.

Suddenly the wind seemed to the pushing her, far more than the Doctor's strength. Donna found herself clutching his arm as she narrowly avoided being knocked straight into a nearby tree.

"Are you alright?" the Doctor asked as she grabbed the tree with her other hand, trying to maintain her balance.

She nodded, gasping for breath.

"It's our fault...Nerys...and the weather?"

"'Course not. Whatever's happening, we're getting in their way. So we have to make sure we keep doing just that. Come on!"

"Whose way?"

But he was steering her along again and now the TARDIS was in sight. Half dragging each other, they burst through the doors where Jack and Jenny were sitting in silence. The door blew behind them with such force that it took Jack and the Doctor's bodies to close it again.

"Are you ok?" Jenny asked.

"At the moment," the Doctor's voice, despite the exertion, was calm and cold as he surveyed her, "no one's ok. And until you start talking..."

"I don't know what to say! What do you want me to say? That this is all down to me? We have to get out of here, that's all I know!"

"We don't run away," the Doctor said shortly.

Donna stared at them and the open anger on each face. She'd seen them argue before. She'd seen Jenny do everything in her power to assert herself. But she'd never seen them like this.

She hadn't realised that tears were running down her cheeks until Jack put a hand on her shoulder and shook it gently, as if trying to wake her from a bad dream.

"What's happened?" he asked and something in his eyes told her that he wasn't looking forward to hearing her response.

..............................................................................

"It's not their usual modus operandi to steal babies," Jack said.

They were sitting around the console.

"Well if you're saying that all fairytales are suddenly real," Donna said bitterly, "what about changelings? Children being swapped by fairies...that's what happened here, isn't it?"

"That's a myth," the Doctor said dismissively.

"Oh that's a myth! Well tell me, Mr Clever...how exactly are we supposed to figure out what's real and what's not?"

The Doctor didn't take the bait and deep down, Donna had to admire him for it. She knew she was being unreasonable but that didn't make it easy to stop.

"Because I'm telling you," he said calmly.

"Well, tell me faster then! I promised her we'd help, remember?"

"No." The Doctor looked at her seriously. "You promised her you'd get her baby back. That was a big promise to make, Donna, when you didn't know what we were up against."

"But..." Donna stared at him, feeling as if he'd unbalanced her somehow, "you knew there was something wrong. I knew you'd know what to do. I mean..."

"I do," he said, stopping her frantic train of thought, "at least, I hope I do. All I'm saying is that sometimes you need to think before you promise that everything's going to turn out alright." His face clouded over slightly.

"Well it will. She's my friend. I know I can help her. Doctor?" She was nearly afraid to ask the question.

"Yes?"

"That baby...if it's not Ellie...what is it?"

"It's one of them."

"But you said changelings were a myth."

The Doctor rubbed his forehead tiredly. "I've never seen this before. Since there's been humans, there's been fairies. You co-exist and in many ways, it's a symbiotic relationship. They feed off the energy that your relationship with time provides them. In turn, they provide a balance between time and nature. And that gets disturbed. Sometimes you cause it. Sometimes they do. Sometimes, it just happens. You're important to each other. But you're also a very real threat to the continued existence of each other."

"But they steal children," Jack said.

"They have Chosen Ones, yes. And they'll fight to the death to protect them. But this is different. This isn't anything I've ever seen them do before."

Donna blanched inwardly at the sober expression on his face.

"So why did we leave that baby there, with Nerys and her family?"

"Did you want to be arrested for kidnapping?"

"They're not safe!"

"They're perfectly safe. For whatever reason, that creature is where it wants to be, or where the rest of them want it to be. No one will get hurt as long as they protect it. That's what I told Nerys before we left...to act like everything's normal, to care for the child just as she would for her own. It's our only chance of buying enough time to work out what's going on here."

"It's not enough! We can't just leave them!" Donna turned blindly towards the door.

But Jack was there first. He stood in front of the door blocking her entrance.

"Let me out!"

"You need to listen to the Doctor first! Donna, these creatures could destroy the whole earth right now if they decided to. We can't track them. We can't stop them. If that child in there gets hurt, we're dead. And the rest of the world is at their mercy."

"But she's my friend!"

"I know," the Doctor said, putting a hand on her shoulder, "believe me, Donna, I do know."

"So what do we do?"

"We're going to find them," the Doctor said, "we're going to ask them, fair and square, what's going on."

"Doctor, you can't just reason with..."

"I can reason with anyone, Jack, I've got reasoning down to an art form." For some reason he turned to stare at Jenny.

"Everyone gets one chance."

"Good luck with that then," Jack muttered.

"I'm going back to check on Nerys first," Donna said.

"No!" The Doctor held her shoulder tighter. "Donna, you don't go anywhere without me. Do you hear me?"

"What?"

"I mean it."

"I'll go with her," Jenny said and Donna suddenly realised that the blond girl had been remarkably quiet since their return to the TARDIS. She smiled at her and started to speak but the Doctor interrupted again.

"You'll do nothing of the sort!"

Donna turned to stare at him. His voice was hard and cold as he surveyed Jenny.

"She's only trying to help."

"Yeah." The Doctor sounded as near as he ever got to sarcastic.

"I didn't do anything!" Jenny's voice was high-pitched with frustration. "It's you who won't trust me with anything!"

"Doctor, leave her alone," Donna muttered.

"Never mind that now. Donna, this is important. When we go out there, you stay with me. If I'm out of sight and Jack's out of sight, you find one of us. Quickly. Very quickly. Got it?"

"Very gallant of you both but..."

"Got it? Or I lock you in here?"

"I'd like to see you try!" She looked at his face again and realised that he was probably capable of carrying out the threat.

"Ok, fine, whatever. Let's go."

Jack pulled the door open.

For a moment, all she could see was sunlight on water and it was blinding her. There was a second when she wondered how they could have travelled, how the TARDIS had managed, once again, to take them to some unknown destination without so much as a whispered direction. She turned to stare at the Doctor in bewilderment.

"Where are we?"

The Doctor was staring straight ahead with an expression on his face that was almost frightening. He didn't reply so Jack obliged.

"Donna, I'm afraid we're...we're right where we were a few minutes ago."

Donna looked wildly around and suddenly realised that he was right.