"Sir," Private Newman looked nervous, "you asked to see me." He stood in the doorway of the small control room, as if afraid to come too close. He was a poor choice of accomplice on such a mission but his expertise had won him the confidence of the pilots. Without that, neither of them would have gotten on board.

"Yes," Professor Anderson stood up, "I want to know about your progress. You're monitoring the machine?"

"We're fairly sure it's fully operational, Sir."

"Fairly sure?"

"Well...without testing it. It will take..."

"Never mind," he said impatiently, "you can give me a detailed report in writing. I happen to know that it is working perfectly.

"Sir?"

Professor Anderson didn't elaborate. No point terrifying the man. Yet.

"I want you to write something down."

Newman hurriedly produced a typepad.

"Miss Stokes," the Professor began, "before you undertake to assist your new found friends in their endeavour, kindly remember your little friend and her little secret which you were so desperate to conceal from us..."

"Stokes," Newman interrupted, forgetting himself, "as in Agent Clara Stokes? Sir, we have no idea where she is! She's in exile! You...you fired her." He trailed off.

"Donna Noble confirmed that Clara Stokes is in league with him," the Professor said calmly, "I want this message given to her when she arrives here with him."

"Here, Sir? She can't possibly arrive here! There's no way."

"But she will, Newman. Look," he produced a photo and passed it to the younger man, "this photo will be taken in three days time."

"Three days...but that's this room! How would that be possible?"

"Exactly."

"Sir, you need to destroy that picture." Now Newman sounded terrified, "the machine is still delicate. You can't walk around with a photo that hasn't been taken yet! How did you get it?"

"Never mind that," the Professor calmly tore up the photo.

"And the man? Is that him?"

"Precisely. Now, may I continue?"

"Of course, Sir. Sorry Sir." Newman kept his eyes firmly on the typepad.

...

"What did you say?" Donna Noble said, her voice rising on each syllable.

"I said," the Doctor was staring intently at the console screen, "I thought we might have a go at becoming parents."

Donna backed away a few steps, "what part of that sentence could I have just heard wrong?"

The Doctor looked up at her. He had that expression she'd come to know so well...his mind was in about a million different places.

"This place we're going to," he said thoughtfully, "well, eventually, it involves a spaceship. And about 200 children. And a few sets of parents."

Donna sat down, "Doctor, call me thick, but I'm not getting this. We were on our way to the time agency."

"Well, in a way. We're going to the year 2075 because the Time Agency are going there. It's one chance in a lifetime to get the big wigs all in one place and time at once. Very hard to track them down otherwise."

"So...children and parents fit into this, how?"

"2075..." The Doctor sat beside her, "it's a really important year on Earth. First of all, you're all under threat. Asteroid. Heading straight for you. You get ten months warning."

"Oh God!" Donna immediately thought of her mother and granddad then realised he was talking about over 60 years from now. The thought made her feel a bit lonely.

"Is that it?" she asked timidly, "does it...destroy the earth?"

"Oh no! It gets knocked off course...just skims past you in the end!"

"Right...good," Donna said uncertainly, "and so?"

"It's what happens as a result of that threat that's important," the Doctor said, "there's the usual things...underground shelters, ingenious, as it happens. Weapons you've never developed before. See, by then, you're on speaking terms with five or six other civilisations. You get good advice! Armies take control...law and order are a bit of a problem. And behind the scenes, there's a little experiment going on. 200 children...sons and daughters of the most elite and influential. Evacuated, just like the second world war, except this time it's to another planet!"

"Which one?"

"Vira...remember the haunted house? Lovely planet, that one. And, most like Earth of all the planets they're in touch with. The plan is sold to the parents, literally sold, I might add...that their children will be kept safe etc. etc. But really, it's insurance."

"Insurance?"

"For the survival of the human race! The human population faces a big decline at best...if the asteroid hits, what's left of them will be dramatically altered, wouldn't you say? Trying to survive in the wilderness. The plan is that these children will be nurtured and educated, best of everything, and returned to earth to keep the population going and hopefully, to save what's left of it and of course, to populate it further. Rule it even, if you like. Restore some civilisation."

"Yeah but...the asteroid didn't happen. So the children just come home?"

"No. That's the thing. See, it takes massive amounts of money and manpower and what have you to get those children off the planet in ten months. The Earth is still in an uproar long after the threat has passed. It's going to take years to get them back. And when that time passes, the children don't want to leave, their foster families want them to stay, and it's not worth the time or money to send for them if they refuse to go."

"They didn't want to come home?"

"Well, not then. Later on, they do and it's organised, through Vira this time. But by then, the children are grown up and married and have children of their own! And most of them have married Virans! Do you see, Donna? They're the first humans to reproduce with other species! It's the beginning! 'Course, typical humans, when they get back to Earth, no one wants to know them. No one knows what to do them. The children, not being complete humans and their parents...who barely remember Earth anymore. They don't fit in anywhere. So they travel further...and this creates a curiosity and finally an acceptance among both humans and Virans. Takes a few more generations, a good few, but finally, you're all going out there and..."

"Mingling?"

"Exactly!"

"Weird..." Donna digested the information for a moment.

"I still don't get what we're doing though."

"Yeah...well, fast forward on a bit...to the 50th century, and you get the Time Agency! Fairly pointless and potentially dangerous with their arrogance. But basically harmless...they're the first human organisation to figure out time travel...so they go back and forth, buying, selling, interfering, creating havoc...you name it. Skip to the 51st century and they get slightly less harmless...human experiments, corruption, exploitation...anything they can get their hands on. And a certain branch of them reverts back to the old human as supreme race ideology. Suddenly, they don't approve of the mingling...mingling which started with a group of 200 children."

"So they're trying to...interfere?"

"Basically yes...I had hints of it, and then when Clara mentioned a Paradox machine..."

"What's a Paradox machine?"

"It's a machine that halts the consequences of a paradox...you and your six year old self being together, that was a paradox. But in a sense you were protected because the rest of the world was gone haywire, and because that change you made, was meant to be changed! What the Time Agency are doing, well that's huge! They figure that they can stop the children reaching Vira and the whole mixing of species is delayed by another few generations...by which time they can control it. Cancel out whole generations...whole species come to that!"

He paused, looking thoughtful. He also looked angry, Donna realised.

"They haven't created a Paradox machine, whatever they think," he said finally, "only Timelords could do that."

"Is that fact or some sort of Timelord pride?"

"Fact," he said shortly.

"And we have to...?"

"Get on that spaceship," the Doctor said, "travel with them. We won't know who the imposters are, but they'll be there. And they think that Jack is me, that's a bonus, for a while anyway! Fifteen sets of parents travelled with the children...16 now!"

"Didn't all the parents want to go?"

"They couldn't," the Doctor said, "the children were the priority...any adults with them were just for education purposes at the other end."

"Doctor, I'm terrible with children. I never even babysat when I was younger. They do my head in."

"You kidnapped a six year old last time my back was turned!"

She smiled slightly, "yeah...that was me. And I had sort of a script to go on. And it only lasted about half an hour."

"Still though...you as a six year old. No easy task."

"Oi!" She swatted him with her hand.

He looked at her seriously, "it's not going to be easy."

"Oh you think?" She raised an eyebrow at him.

"No. Really. It's quite dangerous there. I mean, we'll have the TARDIS and everything but still...it's risky, ok? You need to know that."

"I get it."

"You're sure you want to come?"

"Yeah, 'course I do," she said, "I mean, if you could have left out the babysitting and all, but anyway...what about Clara's friend? We said we'd try and help her."

"Hopefully that'll be part of the process," the Doctor said, "keeping the children safe has to come first. But we'll have them all there...the Time Agency." He made a face, "we're bound to track her down."

"So what do we do? Get one of the kids to pretend we're its parents?"

"Basically, yes!"

"And how do we do that exactly? What child is going to agree to that?"

"Speak for yourself!" the Doctor said, "anyway, there's always one!"

"One what?"

"We'll know when we meet him...or her."

"So...we have to, you know, pretend we're married?"

"Yes," the Doctor said nonchalantly.

"Call each other dear and all that?"

"Yes. And you know what else?"

"What?" Donna asked nervously.

"You can't hit me!"

"Don't count on it," she muttered.