Disclaimer: Sadly, I have no claim on Doctor Who and make no profit from it.

Some plot points and bits of dialogue respectfully borrowed from the episode "Partners in Crime" by Russell T Davies. With apologies to Donna Noble, who I'm sure will find the Doctor someday, just not today.

The Doctor and Adam looked up, startled, as Rose and Martin burst into the closet. "Oi, I told you not to wander off! Where have you been?"

"Unraveling an alien conspiracy," she replied nonchalantly. "Doctor, you remember Martin Jones."

"Nice to see you again, Doctor Smith. I got this off of Matron Cofelia – Miss Foster. Do you know what to do with it?" Martin said all in one breath, thrusting the sonic pen into the Doctor's hands. The latter studied it for a minute and then set to work on the computer while Rose gave him a rundown of what she had learned from the nanny.

She had just finished her explanation when a computerized voice announced, "Inducer activated. Initiating emergency parthenogenesis."

"Does that mean what I think it means?" whispered Adam.

"I think there are about to be one million Stacy Campbells," the Doctor replied grimly as lights began flashing on the computer tower. "The sonic pen gave me access to the system, but I still need a way of blocking the activation signal. Think!" He ran his hands through his cropped hair, even as Martin did the same with his wild mane.

"What if…" Martin began, but the Doctor interrupted.

"I've got it, the pendant!" He pulled the object from his pocket triumphantly. "See, Martin, you were right, these are much more than ornaments. I can wire this into the system like so," he explained as he matched words to actions, "And use it to override the signal." He rocked back on his heels, surveying his handiwork with satisfaction, and the others all grinned at each other. But the good feelings lasted only a moment, until the lights began flashing more insistently and the Doctor yelled, "Nonononono!"

"What is it?" cried Rose.

"She's doubled the signal! She's overriding the override! We don't have enough power to block it! I can't…" But at this point the Doctor trailed off in astonishment, because Martin had reached around him and wired his own pendant in right next to the Doctor's. "Wha–? How did–? That did it, you stopped the signal. How did you know what to do?"

"Oh," Martin shrugged modestly, "I didn't really, I just copied what I saw you doing."

The Doctor gaped at him, and then noticed Rose behind Martin, pointing and mouthing, "My Doctor." His flabbergasted gaze flicked between the two several times before he managed to snap his jaw closed and give Martin his broadest smile. "Right, good thing we have you along, Martin Jones, well done."

They all looked back at the computer as a new noise issued out of it. Rose heard Martin draw a sharp breath at the same moment that the Doctor did, but pretended not to notice. "What is it, Doctor?"

"Oh, she's in trouble now! Come on, to the roof!"

They arrived on the roof just in time to see Matron Cofelia ascending after the Adiposian babies in the blue light of a tractor beam. The Doctor tried his best to talk her down, to convince her that her employers were planning to tie up loose ends by eliminating their accomplice, but she disregarded him right up to the moment that the beam shut off and she plummeted to the earth.

Martin found that it was somehow his shoulder that Rose had buried her head in when she flinched away from the gruesome sight. He was a bit surprised by this turn of events, but certainly wasn't about to question it or push her away, although he did keep a wary eye out for any jealous Time Lords in the vicinity. "We didn't save her," he heard himself murmuring a bit brokenly.

Rose lifted her head. "We did what we could. She chose not to save herself. It's not your responsibility," she said firmly.

There was a moment of silence while they all absorbed the events, and then the Doctor grinned. "But you did just save a million people, Martin. Plus Rose, which has got to count for almost as much. Not bad for a day's work, not bad at all. I'd say he deserves a reward, wouldn't you, Rose?"

She smiled up at Martin wolfishly. "Oh, most certainly, he does!" And before he knew what was happening, she had pulled him in by his lapels and pressed her mouth enthusiastically to his.

He froze, unable to respond, voices clamoring inside his head. There was the one that said that nothing this wonderful could possibly happen to him, that what appeared to be Rose was probably a shape-shifter who would morph into a piranha the next instant. Then there was the one that told him to be ready to flee the wrath of the Ninth Doctor as soon as Rose was out of his arms. And a third insisted nastily, It's not really you she is kissing at all, it's the pretty human she thinks you to be.

When she finally pulled away, an eternity later and much too soon, he was afraid to see her hurt by his lack of response. But she was unfazed, grinning up cheekily at his stupefaction.

"Rose, you… I mean, that… I… What about…" He cast a nervous glance toward the Doctor, fully expecting to have to dodge a flying fist. But oddly, the other man was wearing a daft smile, which only added to Martin's confusion.

"Oh, don't worry about him," Rose said dismissively. "He doesn't mind who I kiss. He knows I don't belong to him." He did know that, Martin thought, had always known that, but it didn't mean he didn't mind. She continued, "Anyway, who would choose a moody old alien when they could have a pretty young human?"

That echoed so painfully his own internal voice. Who indeed, he thought glumly. He wasn't sure why the idea bothered him so much. It wasn't as if he could keep this version of Rose with him anyway. She would go on traveling with Nine, and eventually with him, right up until the day he lost her. He couldn't snatch her away from her future, his past. And she may not love her Doctor now, he tried to console himself, but she will do. She told you as much at Bad Wolf Bay. But the large part of him that was self-loathing insisted that she couldn't possibly have meant that kind of love, the kind he had for her.

He was distracted from all this turmoil by Nine's laughter. "Well, go on, answer her. Might sound like a rhetorical question, but it's not, you know."

Apparently, Martin's brain had decided to take a vacation, because all he could manage in response was an owlish blink at the Doctor and a stupid "What?"

Rose cupped his face in her palms, and he couldn't stop himself from closing his eyes and leaning into her touch. Blimey, it was going to tear out both his hearts to leave her again, but at least this time he would carry the memory of her kiss, of her warm hands against his cool skin. She was speaking, and he forced himself to focus on her words. "I asked who would choose a moody old alien. The answer is: I would. I do. Every time."

His eyes flew open at this, found hers, but once again all he could say was "What?"

She laughed, a sparkling, joyous sound, and glanced over at Nine. "See what kind of eloquence you have to look forward to in your next incarnation?" She beamed up at Ten in gentle amusement. "I am not your past, you plum. I am very much your present. And these two aren't your anything. They don't even belong here, except that they were kind enough to give me a lift."

Her words finally cut through his mental fog, and he caught her hands in his, scarcely daring to hope that he had actually understood her. "You…you know who I am? You are my Rose?"

"Of course I know you, Doctor. And yes, I am your Rose, fresh from Pete's World."

He had no words, just pulled her to him in a crushing embrace until she began squirming and a laughing, muffled voice said, "Easy, Doctor! Human here. No respiratory bypass."

"Oh, right, sorry!" He released her from his arms but took her hands again. "Oh, but wait! The universes, the walls between…"

"…Are in no danger. I promise, I'll tell you the whole story of how I got here later, but for the moment, just believe me when I say that everything is fine."

"And your family?"

"Still back in the other world."

"You left them?" he asked wonderingly. It was one thing for her to choose him in the heat of the moment at Canary Wharf; it was quite another for her to make a deliberate and thought-out decision.

"Yes. And I won't pretend that it won't hurt. But it hurt worse to be without you," she told him quietly.

He closed his eyes to let the wave of emotions wash over him, then wrapped his arm around her shoulders, pulling her tight against his side, and turned towards Nine. "And you – you agreed to bring her back to me?" He couldn't imagine anyone who had known Rose for more than five minutes letting her go without a fight.

His counterpart seemed to read his thoughts and gave him a compassionate smile. "Like she said, she doesn't belong to me. Another time, another place, maybe I would have battled you to the death over her, but I knew from the start where she was meant to be."

"Thank you," Ten said simply, his tone conveying far more than the words ever could.

"Right," said Nine brightly, "Well, Adipose problem solved, star-crossed lovers reunited – I think our work here is done, Adam. You know I never like cleaning up the mess afterwards, so we'll leave you two to that."

Rose pulled away from Ten to hug the two men and whisper her gratitude and her goodbye, and then they were gone, leaving Rose and her Doctor alone on the roof. He stood for a long moment, just basking in her presence, wonderment on his face. Then he reached out his hand and she took it in hers, and he marveled at how well they fit together. "Right, back together again! Next stop: anywhere you want. TARDIS is just around the corner. Come along." He turned to go, tugging her after him, but was brought up short when she didn't move.

"No," she said, so softly that he barely heard.

He turned back, puzzled. "What's wrong?"

She was staring down at her feet, looking shy but very determined. "Before we set off again, before we get caught up in mad adventures where we don't have time to think, let alone talk, I just need to know. I need to know where we stand. Because I told you how I feel that day at Bad Wolf Bay, and then we got cut off. I just need you to…to define us."

Had it been only yesterday that he had told himself he wouldn't waste a second chance if it were offered? Now that the second chance was impossibly right in front of him, he panicked. His instinct told him to run, fast and far. It wasn't fear of commitment – in his hearts, he was already committed to her for life. It wasn't fear of the pain of eventually losing her – he was sure that losing her in the distant future to old age could hurt no worse than losing her right now to his own stupidity. It was fear that he was not enough, that he couldn't possibly be the man she needed, she deserved. He feared that someday he would do something to shatter her image of him, that she would come to see him as he saw himself in his darkest moments. He feared her disillusionment.

He managed a strained smile and tried for a light-hearted tone, although he knew he wasn't entirely successful. "Bit foolish to wait till your ride has already left before you ask that. What if you don't like my answer?"

He expected a cheeky retort, but she remained serious, although she did manage to look up and meet his eyes through her lowered lashes. "It doesn't matter if I like it or not. I'm not giving you an ultimatum. I am with you forever, unconditionally. And I'm not trying to make you say something you don't feel, or feel something you don't want to. If you say we're mates, then we're mates. I just need to know what to expect. I need you to tell me how you see us."

This was his out, he thought with relief. One word, and their relationship was back to what it had been. He could do mates. He already had several years' experience being Rose's best friend. It was something he knew he could succeed at. It was safe. It was a role he was confident he could fill. It was…so much less than she deserved, he sighed inwardly. After all she had done for him on their travels together, after all she had sacrificed to return to him, what Rose deserved was for him to face his fears and do his very best to be what they both wanted him to be, to give her the relationship they both wanted to have. He still wasn't convinced that he could succeed, but he could certainly try his hardest. It terrified him more than an entire fleet of Daleks, but for her sake – and honestly, for his own too – he would do this. He just had to get the words past the tightness in his throat.

But apparently he had waited too long to come to this conclusion, because Rose was talking again now, running her gob as if – well, as if she were him. He was a bit confused. Rose wasn't usually a babbler. "Listen, I know you're thinking that I'm going to go all domestic on you. But honestly, this doesn't have to be a big, deep, complicated discussion. Just a word or two is all I need, and then we never have to talk about it again. And I know that the last time you saw me, I was all emotional and crying and stuff, but really, that was the worst day of my life, well, the second worst day, right up there with Canary Wharf, and you know that I'm not usually like that. And don't worry, I won't hold you to whatever you were going to say that day. I mean, for one thing, you thought you were never going to see me again, and people say all kinds of things when they think it's for the last time. And then for another, a long time has passed. Things have changed. Maybe you've had other companions since then."

He grasped at one phrase from the torrent of words washing past him. "I did have another companion for a while. Martha, her name was, Martha Jones."

"Oh," she said in a voice that seemed to him uncharacteristically small. He couldn't imagine where the babbling had come from, let alone why it had suddenly switched off; perhaps she was having a delayed reaction to the dimension hopping. "Wait," she was continuing, "Martha Jones…as in Martin Jones? It was her name that you used?"

He gave a sheepish smile. "Well, John Smith was taken, so I had to think fast." She looked away, and he thought he saw some moisture in her eyes. He didn't know what to make of that either; maybe she was already second-guessing her decision to leave her family for him. His throat clenched at that thought, but he soldiered on. "Anyway, you would have liked her. She was a lot like you, actually. Brave and clever and didn't put up with much guff from me." That earned him a wan smile. "We got into some tight scrapes, she and I, but she always stuck by me. Loyal to a fault, she was. Fancied me, too."

With every word, he could see Rose deflating more and more, shrinking in on herself, and it finally hit him why, what she was thinking, where she imagined his story was leading. She had promised to stick with him forever, regardless of his answer, and she meant it. But that didn't mean that the wrong answer wouldn't break her heart. You're making a right hash of this, you are, he chided himself, and rushed to get through the rest of his explanation. "But eventually she gave up and went home. Because she knew that I could never fancy her…" He caught her chin and gently lifted it to make sure she would look him in the eyes for this part. "Not when I was so caught up in fancying you."

In an instant, the light returned to her eyes, and she threw her arms around his neck. He willingly returned the embrace, but leaned back out of reach of her kiss. "Wait just a minute. Before the universe conspires against us again, I want to say this properly – no more hinting or implying or leaving you to infer." He took a deep breath and then plunged ahead, "What I wanted to say that day, what I want to say now, is: Rose Tyler, I love you. Now and forever, and from the bottom of my hearts."

The blinding light of her smile chased away the last shadow of fear and self-doubt. He grinned down at her. "There, I've said it, and the universe didn't implode, and the walls of reality didn't collapse! So now, Rose Tyler, you may snog me to your heart's delight."

Now it was her leaning away, eyebrows arched. "Oh, may I? The great Time Lord grants permission, does he?" she asked, but with a teasing tone that assured him that she was not truly offended.

"Quite right, that was poorly worded. How about this instead: Rose Tyler, I humbly request permission to snog you to my hearts' delight." He winked at her, and leaned in close to whisper, "But I must warn you, I have two of them."

"I think I can handle it," she murmured.

And, as it turned out, she could.