A.N. - The dialogue of this is taken from the Doctor Who Christmas Special, word for word, but everything else is my own artistic liberty. I felt the need to explain what had happened when he'd regenerated and how he had coped with it. This piece is near and dear to my heart, so if you feel the need to tear me down, to get in my face about how Rose's love never changed, please don't. This is called fan fiction, my dear readers. Written by fans, for fans. And it's fictional. This story is just an analysis of what I think must have happened for the Doctor because he was in love with Rose when he regenerated, so please enjoy!

When Things Changed

Rose couldn't believe what this stranger was trying to tell her. There was no way that this man was her Doctor. He may have worn his clothes, but it was neither his face nor his voice that emerged from the facade of the shirt and leather jacket that he still wore.

"You can't be," was all she was able to manage, but the stranger already had an answer.

He walked towards her, the look in his eyes serious.

"Then how can I remember this? The very first word I ever said to you. Trapped in that cellar." Her heart stopped. "Surrounded by shop window dummies. Ooh…such a long time ago. I took your hand…" He lightly grasped her hand, not noticing her slightly disturbed reaction to feeling a hand she hadn't felt before. "…And I said one word. Just one word, I said…Run!"

And for a brief moment, she could see the flicker of the man that she knew before; the man with blue eyes and a northern accent.

"Doctor?"

He smiled.

"Hello."

Her heart started again, but it immediately plummeted at hearing that one word, suddenly realizing that it was the same person…but not the same man that she knew.

"Oh my god," was all she uttered as she sank back against one of the supports inside of the Tardis.

"And we never stopped, did we?" the Doctor said, rushing around the console of the Tardis. "All across the universe! Running, running, running, and that one time we had to hop! D'ya remember? Hopping for our lives!" he added, hopping up and down on one foot, "Yeah, all that hopping? Remember hopping for your life? Yeah? Hop, with the…? No?" But at seeing her reaction, the smile that had previously been plastered on his face as though with glue, diminished, as did his hopping.

And then she asked the question that he'd never been asked before.

"Can you change back?"

"Do you want me to?" he quickly replied.

She nodded and said, "Yeah."

He wasn't prepared for that answer. He'd never changed while being in love with his companion. It was a new experience for him, something that was extremely hard to come by, considering his nine hundred years of life, and he wasn't sure how to respond.

"Oh…"

"Can you?"

"No."

The instant he said the word, he saw something inside of her shift. And he knew what it was. And it's exactly how he would have reacted had he found her in another body. He should have realized and remembered that humans made strong associations with appearance and sound. And now…he was different.

And her feelings towards him had inevitably changed.

Scared to ask, but knowing that he had to give her the choice, he asked anyway.

"Do you want to leave?"

"Do you want me to leave?"

"No!" he said, a bit too quickly perhaps. "But, your choice. If you want to go home." She didn't seem to remember the kiss, which bothered him, but at the same time, considering how she was reacting to his regeneration, it was better that she didn't remember because it would make it even harder.

He moved to the console, saying, "Cancel Barcelona. Change to…London, Powell Estate…ah, let's say twenty-four December. Consider it a Christmas present."

She was giving him an odd look, and he knew that she was sizing him up, mentally comparing him to the man that she'd known before, and he had the faint feeling that she found him lacking, even though to his mind he was still the same person.

"There."

The Tardis began its revolutions through the space-time continuum, and Rose continued to stare at him.

"Going home?" she said, sounding confused.

"Up to you," he said, arms crossed over his chest. "Back to your mum? Still waiting? Fish and chips, sausage and mash, beans on toast. No! Christmas! Turkey!" But then he corrected himself, saying, "Although, having met your mother, nut loaf would be more appropriate…"

A faint smile.

"Was that a smile?"

"No."

"That was a smi-ile."

"No, it wasn't…"

"You smi-iled."

"No, I didn't."

Frustrated, he said, "Oh, c'mon! All I did was change, I didn't…"

And that was when things simply went dark and manic. He could feel the two parts of him fighting for dominion. His Ninth incarnation felt as though it was fighting against who he was supposed to be, now, and who could blame him? It was obvious to him that that was what Rose wanted as well.

He was manic, he was channeling his new self, of that he was certain, while his old self seemed to screaming at him internally to let him come back to the world to be with Rose, where he belonged, but just as all of his previous regenerations, he was being slowly being silenced by the new cells that were attempting to put themselves into their new places, where they were supposed to go…and yet, still, his Ninth regeneration raged at him, and he almost gave in, forgetting just how strong that part of him was.

His Ninth was easily the strongest so far of all his regenerations. The one most capable of doing the double genocide that he'd done once before. He was powerful, unstoppable, and seemed almost desperate to get back to Rose…and he nearly gave in a second time.

The next few days were hell, but then he was fully regenerated, thanks to Rose and her mother.

However, even as he showed her New Earth and the apple grass, he could see straight through her smile and feel the pain that was settled behind her gaze. Even though she tried to hide it, he knew that it was there, and he wondered if it would ever, truly, go away.

He loved her. Irrevocably. Completely.

But her love for him…was not the same anymore. If there was any at all.

He would try to help her understand that it was still him, but he had no idea if he could succeed. Yes, he'd changed while having companions before, but he'd never been so desperately in love with one like he was with her. Oh, yes, he was well aware of the fact that he was in love with Rose Tyler, but as his previous regeneration he'd never found the courage to tell her…but he felt he'd done it every single time that he'd told her that she was fantastic, or grabbed her hand as they'd run through their' travels.

It was the only way he knew how to tell her.

But now…now there were no words. No words at all to try and explain what was happening between them. Because of his regeneration, things were inevitably different for her and always would be. And the heartsbreaking part of it all was that he could do nothing to change it.

His new self was happier than his old self had been; the personality was such that he couldn't help but try and keep a bit more of a sunshiny outlook on life, whereas his previous regeneration had been so much more pessimistic…no, that was the wrong word. Realistic. That was the word that he was looking for. He'd seen the universe for what it was and had taken it on as it came, but now…now he wasn't that way anymore.

In the past…well, the past as humans could conceive of it, he'd never been bothered by the fact that his personality changed as well as his body, but now it bothered him. And it wasn't supposed to. And that bothered him.

Rose had changed him in more ways than one, which was something that he simply couldn't cope with in his new form.

He'd changed who he was before, but now he was someone who didn't need to be healed any more. He wasn't entirely sure how she was going to cope with that, because she was someone who lived to heal, though she didn't realize it, yet. She made people feel…better. Stronger. And at the same time, made them feel that it was okay to not be perfect. Which was why he was no longer the person that she needed in her life.

She was a healer.

But she'd fixed him, and before he could move on with her in the way that he'd hoped, he'd changed on her…and was left with no scars to show the man who he was before.

And he didn't know if he could live with that. He didn't know if he could live with being the happy, go-lucky friend for the time being that was trying to earn back her trust in a stranger's face. It was like he was wearing a mask that he couldn't tear off, and he knew that she knew it as well. He saw the looks from the corner of his eye when she thought that he wasn't looking.

He saw the longing and the pain behind her eyes. Whenever she casually touched him, it was no longer with the ease and familiarity that he had come to cherish, but now it was filled with a hesitance that made his hearts break. Like she was around a stranger. Which to her, he supposed, he was. He had a different personality, not just a different face, and he had become someone that she no longer could fully rely on simply because of the fact that he had changed.

And, for once in all of his nine hundred years of life, he wished he wasn't a Time Lord.

He wished that he had simply been human and never changed. It had morbidly crossed his mind that perhaps he should have simply died, instead of regenerating; at least death had a process. Mourning, anger, denial, acceptance…or something to that effect. He wasn't entirely sure of the order himself, but it had to be better than what he was putting her through right now.

All of this ran through his head as they lay on their backs in the apple grass, his mind working at light-speed compared to a human's, and he wanted nothing more than to shut it off and sit beside her and enjoy the moment…

…But he couldn't.

He could fake it all that he wanted, but both of them knew the truth.

That they were terrified.

There was the old adage, of course, that said that life moved on, but as he was a Time Lord, it made it a bit more extreme in his case, and all the more difficult. Maybe, possibly, they might go back to where they were when they first met…but he knew that her love for him, if it did come back, would be different from the all-encompassing trust and faith that she'd had in the beginning. There might be respect, and a short and sweet sort of love that could shine between them, but it would never burn as bright as it had before.

Their first kiss had held all of time and space in it, passing between them, giving life to one and death to the other, and the love that he'd felt in that moment told him the truth of her feelings for him.

Before, they had been fire and ice, and rage…like the night and the storm in the heart of the sun. Their love had been ancient and forever, and it had burned in the center of time for a few brief moments, an eternity that was nowhere near long enough for either of them, as it saw the turn of the universe, which was undoubtedly turning around it…

…And it had been wonderful.

But now, or someday in the future, it would be a mere flash of flame in a too-clean fireplace that showed no signs of use or of wear and tear.

A mere shadow in comparison as to what it had been between them for those brief moments that they'd made.

And he would treasure it in his hearts forever, and silently vowed to himself that if….no, when he lost her, that he would never give his heart that fully again. That it would be superficially given, only, and in a large enough amount as to fool anyone who dared to look at it too closely.

He had two hearts…and Rose Tyler had stolen both of them a regeneration ago when she'd looked up at him and said, "Better with two."

Yes.

Things had changed.

And he couldn't change them back.

She glanced up at him then, and he bit the inside of his cheek, swallowing convulsively, feeling the emotions lingering all too near to the surface, and he fought back the tears that threatened to fall and destroy the tentative friendship that they had just regained.

He flashed her a carefree smile.

Yes.

Things had changed.

But he could pretend, at least, and silently wish for another disaster to strike so that he could become the man once more that she had fallen in love with. He'd never repeated a generation, which was actually odd, in and of itself, as it was common to repeat one or two among the Time Lords, but if he could choose one, he chose that one.

However…

…Things had changed.

And he couldn't change them back.

He choked back another tear.

THE END