Disclaimer: I don't own what you recognise; the drill should be familiar to you by now

Feedback: I'd appreciate it; I'm trying to do something a bit different here

AN: Thanks to the stargate time traveller for suggesting the new name for the Doctor's daughter; I had my own idea, but once his suggestion was brought up, it just felt right, both for the reasons Amy reveals here and my own personal fondness for it

The World of Paradox

Sitting in the TARDIS medical bay as she stared at its only patient, still wearing her familiar dark green T-shirt and trousers, Amy wished that she knew more about all this equipment. The Doctor had given her a fairly detailed crash course in some of the TARDIS's more straightforward functions, such as how to dematerialise the ship or treat simple wounds, but he'd somehow never gotten around to showing her the more complex systems, as though he was privately hoping they'd never be needed.

She supposed she could understand that- if she ever had to treat him for the effects of long-term exposure to a crack in reality, the situation would definitely be worse than anything she'd experienced so far- but that didn't mean it wasn't frustrating to be looking at the Doctor's daughter and feel so helpless.

Returning the children to the colony had actually been the simplest part of the day's events; with the Faction members now erased, all anyone remembered was children going missing and a fanatic who'd torn his own heart out as part of his insanity. Once the Doctor had found the equipment that the Faction had been using to maintain the perception filter around the city, it hadn't taken long to deactivate it, leaving him with nothing more to do than take the children back to the outskirts of the colony and depart once he'd made sure that the residents had seen them.

Amy wished that they could have spent more time looking around the colony, but even if she wanted to take in more of her future, she appreciated that the Doctor had to think about the bigger picture right now. Staying anywhere for a long time was dangerous in case the Faction showed up, and staying there when they'd just erased members of the Faction from history was practically asking for trouble.

She just hoped that the Doctor was right about the Faction abandoning their Uxarieus project; they might think of themselves as being above something as petty as revenge, but the ones she'd encountered so far certainly seemed small-minded enough for that…

"Any change?" the Doctor asked, breaking her concerned thought as he walked into the medical bay, looking anxiously at his daughter.

"Not that I've seen," Amy said apologetically. She appreciated how hard this was for the Doctor, both in terms of anxiety over his daughter and keeping the TARDIS outside of time for this long, but even if the Doctor loved travelling, he wanted to be sure that his daughter was safe before he did anything else. "How long could this take?"

"No way to be sure," the Doctor said as he sat down beside Amy, reaching over to take his daughter's hand with a small, sad smile. "I've been through worse and woken up sooner, but I was fully trained before I let Gallifrey; she was born for battle and dived straight into the conflict she was made for, and then I never had the time to really teach her anything…"

"She'll recover," Amy said firmly, placing a comforting hand on the Doctor's shoulder. "She's your daughter; you're too naturally stubborn for her not to have picked that up."

As though Amy's words had been a cue, the girl's eyes suddenly popped open and she sat up rapidly from the bed, her gaze instantly fixating on the Doctor as she registered his presence. As she looked between the two, Amy felt a sudden pressure in her ears, as though she was suddenly underwater, but the sensation vanished before it could become painful.

"D… Dad?" the Doctor's daughter said, looking at the Time Lord incredulously. "That's… is that you?"

"It's me," the Doctor smiled at her, the genuine grin broader than anything Amy had seen him display before. "I know I look different, but it's your dear old Dad."

"H… how?" the daughter asked, looking uncertainly at him as she slowly moved to the edge of the bed, her limbs unsteady as she hauled herself into a sitting position.

"It's a… thing we can do," the Doctor explained, awkwardly rubbing the back of his neck. "When we're faced with imminent death, Time Lords can… change our bodies to save our lives. I thought you were too young to do it, which is why I thought you were… well, dead… after what happened, but your body must have considered your birth as a regeneration of its own and let you heal after I left."

"That helps?" Amy asked.

"We can deal with some serious injuries as though we're still regenerating if they're inflicted in the first fifteen hours of a new body, Pond; when she didn't regenerate immediately, I assumed that… she was just too young to do that properly," the Doctor explained, before he turned back to his daughter with a new urgency in his expression. "I swear to you, if I'd had any idea that you were still alive…"

"I know, dad," the girl said, grinning warmly at the Doctor before she looked at him in confusion. "But… how did you find me, who were those men in… skeletons… and who is she?"

"Oh, I'm Amelia Pond," Amy smiled as the blonde pointed at her in confusion. "I'm… well, I travel with your dad."

"Really?" the girl looked at her in surprise.

"Think of her as… a student," the Doctor said. "She's…been a very good friend to me since we met."

"Oh," his daughter said, looking at Amy with an uncertain expression.

"Just a friend," Amy said reassuringly. "Believe me, I'm not… his attempt to replace you or anything like that."

"As for who the men in skeletons were," the Doctor continued, "they were Faction Paradox, enemies of mine who seek to cause paradox and chaos throughout history; they were attempting to use you as part of a more complex plan to create a group of agents who would be… sensitive to temporal anomalies."

"Oh," his daughter said. "That… sounds complicated."

"And obviously unpleasant," the Doctor confirmed, looking solemnly at his child. "Still, at least they didn't know who you were."

"They didn't?" Amy looked at the Doctor in surprise. "They were using her for-!"

"You heard that Cousin, Pond; they knew what she was, not who she was," the Doctor clarified. "If they knew that she was my daughter, the Grandfather would be here in person to do everything he could to corrupt her into his personal protégé; as it is, she was useful to them as a surviving Time Lord, but they would have had no reason to think that she was anything else."

"Not a nice man, then?" the Doctor's daughter asked with a slight smile.

"Not really," the Doctor replied. "Let's just say he doesn't like me and take it from there; you just lucked out in that he hasn't seen me in the body I had when you were born and didn't bother looking for a name for your father after he'd identified you."

"He didn't even look?" Amy asked in surprise.

"Advantage of his arrogance and certainty that he knows everything about me, Pond," the Doctor explained with a grim smile. "He'd find it easier to imagine that there was another Time Lord out there than that I'd have a daughter and leave her out there."

"But… you did leave me…" the other woman said, looking at the Doctor with new uncertainty.

"Because I thought you were dead," the Doctor said, his expression becoming more solemn as he reached out to take his daughter's hand. "If I'd had any idea about what had really happened to you, I would never have left you behind; I swear it."

For a moment, the Doctor and his daughter stared silently at each other, hands clasped together as they took in the moment, before the Doctor sat back with a smile.

"So," he said with a nonchalant grin, "now that you're here, the most obvious question now is what we call you?"

"Don't you have any ideas?" the girl asked.

"To be blunt, Time Lord names are… very complicated," the Doctor smiled. "Most of them only had meaning on Gallifrey, and since you're not going to be there, it would probably be better if you had a name that's more relatable to the society you'll be in."

"So… you want to give me a human name?" the girl asked.

"If I can think of one," the Doctor said with a shrug. "Keep in mind, you're talking to the man who's used 'John Smith' as an alias for centuries; I freely admit that I don't have much imagination when it comes to giving people names…"

"Melody?"

"Melody?" the Doctor and his daughter repeated, looking at Amy in surprise.

"I just… like it," Amy said, briefly wondering why she liked it before shaking the thought off. "Is there a problem?"

"The name's fine, it's just that we'd probably end up calling her 'Mel' for short, and, well…" the Doctor said, trailing off awkwardly.

"Oh," Amy said, suddenly remembering some of the Doctor's stories about the complicated time he'd had in his seventh incarnation when he had been 'assigned' the role of Time's Champion to escape a dark future. Now that Amy thought about it, one of the things he was still ashamed of was how that incarnation had telepathically influence his predecessor's companion Melanie Bush into leaving him so that he could do what had to be done without her morality 'holding him back'. "Yeah, that… might be awkward."

"What?" the young woman asked.

"Just… bad experience in my past; I'll tell you about it later," the Doctor said, looking apologetically at his daughter. "Now then… any other ideas?"

"Selene?"

"Where did that one come from?"

"After the heroine from the Underworld movies," Amy explained, suddenly slightly awkward about her choice. "I mean, the reasons for it are different, but they're both great at fighting, they both never had a real childhood because of the war their people started, and… uh, actually, forget it; doesn't work."

"Why not?" the Doctor's daughter asked.

"It just… doesn't," Amy said; she wished that she'd remembered the Doctor's complicated history with vampires before bringing the name up, but the best she could do was deflect it before any more awkward questions came up…

"Natalie!" she grinned as another option came to her.

"Natalie?" the Doctor's daughter repeated, her tone thoughtful as she looked at Amy.

"After Natalie McDonald."

"Friend of yours?" the Doctor asked.

"She was a fan of Harry Potter," Amy explained, looking at the Doctor with a slightly sad smile at the story she was about to tell. "I read about her online; she was a fan of the series when it started, and she'd read up to around Prisoner of Azkaban, but she was dying of leukaemia and knew she wouldn't live to read the end, so she wrote to J.K. and asked her what was going to happen to everyone."

"And it didn't work out?" the Doctor asked, the genuine sorrow in his eyes once again reminding Amy why she lo-admired the Doctor so much; he had lost his entire planet, and he still felt sad hearing about the death of a little girl he'd never met.

"Apparently the letter arrived while J.K. was on holiday and her response got to the McDonalds after Natalie had passed away," Amy confirmed sadly. "J.K. struck up a friendship with Natalie's mother, and named a first-year Gryffindor in Goblet of Fire after her as a tribute, but still… I really felt for that story…"

"I like it," the Doctor's daughter said, looking between Amy and the Doctor with a sad little smile. "The name, I mean; I like Natalie."

"I… like it too," the Doctor said, nodding in approval at Amy before he looked at his daughter. "So… Natalie… a few years back and a lifetime ago, I… well, I know I didn't really get around to saying it back then, but now that you're here… well…"

"Can I come with you?" the newly-named Natalie asked, looking at him with an eager grin. "Really?"

"Well, he wouldn't offer if he didn't want you here, and I know that I wouldn't mind some more female company," Amy noted with a smile. "If you want to be here, feel free to stay."

"Yes!" Natalie grinned, moving from the Doctor to give Amy another hug. "Thank you thank you thank you!"

"You're… welcome," Amy said, smiling at the girl's obvious enthusiasm, before she pulled back to look at her more seriously. "Although, if you're going to go by a human first name, what do we do about a last name?"

"What?" Natalie said, looking at Amy curiously.

"Well, your dad gets away with a title, but it couldn't hurt for you to have a last name for just… most of the time," Amy said, shrugging slightly. "Like he said, he uses 'Smith' when he has to, but-"

"Kreiner."

"Kreiner?" Natalie repeated, turning to look at her father. "I thought you said you didn't have much imagination for names?"

"I don't," the Doctor said, his tone solemn as he looked at her. "It's the man who saved my life when I'd done everything wrong in working with him."

Amy knew what he meant by that. He'd told her enough about his history with Fitz for her to be sure that he'd done everything he could in a situation that had just become very complicated very quickly, but so long as he respected Fitz's decision, this wasn't the time for Amy to get into another argument with the Doctor about whether he was worthy of Fitz and Compassion's sacrifice.

"Oh," Natalie said, looking thoughtfully at the Doctor before she spoke again. "He was a good man?"

"The best," the Doctor nodded.

"Then I'd be proud to take his name," the young girl said, smiling in understanding at the Doctor. "Natalie Kreiner… I like the sound of that."

"Me too," the Doctor said, smiling at her as he took her hand. "Natalie Kreiner… welcome aboard."

Looking at the young woman who'd just joined her and the Doctor, Amy couldn't help but smile at the thought of what was coming after this.

The Doctor had lost his planet, but he'd regained his daughter; it was such a small reward for his heroism, but she knew without being told that it was more than he would ever believe he had the right to.

The only thing troubling Amy right now, as she looked at the young blonde enthusiastically embracing her father who looked like he was just about her age, was if she should consider this new addition to the TARDIS a kind of sister, or if she was something else altogether…


AN 2: Getting back to canon rewrites next chapter, as the Doctor faces a race that always forces him to consider the moral complexities of his meetings with them.