AN: so I was watching Doctor Who the Infinite Quest with my little brother, and we got to the part where we almost but not quite see the Doctor's desire, and my brother turns to me and says "It's Rose, isn't it?" Which got me thinking: of course it was Rose.

Disclaimer: Yeah, right, as if it's mine.

His heart's desire. That was a thought. Hearts actually. Both of his hearts had the same desire. Both were beating it out every moment he was alive, in an endless refrain.

Rose, Rose, Rose

She was often in his thoughts, and never more than lately. The Doctor didn't know what Martha might be thinking when she thought of her heart's desire, Probably finally getting to be a real doctor, a voice inside him reasoned, but for him the phrase only conjured up one thing: a blond twenty-one year old London shop girl who was now trapped in another universe. Traveling with Martha made the ache less. It never went away, but it was less.

And now he was on the Infinite. The mythic ship that could give you what your heart desired. It was almost too tempting. Almost. But he was a Time Lord, and he would be strong. No matter what he saw, it was all an illusion. Rose could never come back to him.

Martha was easy enough to find, after he had left Baltazar with Squark. The shriek was one clue. The glowing blue light was another. He would be glad to see her, after three years of attempting to get back and find her. If Canary Warf had taught him anything, it was that nobody gets left behind.

He was slightly shocked to see what appeared to be himself standing before Martha. That was interesting, and unexpected, and worrisome all at the same time. But there was no time for that. And he knew all about time.

"Excuse me," the Doctor said, coming up beside both figures, "that's my friend you're scaring,"

Martha looked as though she was warring between being glad to see him, and being horribly embarrassed that he had seen her heart's desire, and it was himself. A blush spread over her dark skin, and her face set, as if she was determined to carry on in spite of this new and embarrassing development.

I'll have a word with her when we're out of this the Doctor promised himself.

"Can you make him go away?" Martha asked, staring at the glowing version of the Doctor with revulsion.

"That's up to you, I'm afraid, you conjured him up" said the Doctor grimly. He was not, after all, responsible for getting rid of her fantasies, even if they were about him. The thought, which coming from Rose would have sent shivers down his spine and made him grin like an idiot, made him suddenly feel very old and tired coming from Martha.

"But how'm I supposed to…." Martha asked, confused.

"Heart's desire," he replied simply.

"I don't believe I walked into this!" Martha cried, exasperated. The fake Doctor flickered for a second, as if he were a image being projected. The Doctor could practically see the wheels turning in Martha's head as she figured out what she had said. Oh, yes, there was a reason he had chosen Martha Jones. "Gotcha! I said 'I don't believe this'" the blue lights shone out, and he was gone, "Yes!!" yelled Martha, jumping up and down to celebrate her victory.

The Doctor allowed himself a grin in honour of her figuring it out on her own, when another light caught his eye, one that was meant for him alone. He could see her now, Rose Tyler. There she was, coming towards him in all her glory, just as he had left her: blue hoodie, blond hair, soft eyes that he could drown himself in. And he knew that he was lost.

This truly was the desire of his hearts. Rose Tyler, with him always as they traveled the universe together, the good times never ending. He had seen a possible future once before, as John Smith, sitting on that bench with Joan; now he saw another. He saw Rose in his arms once again as he gave her a huge hug, Rose lying beside him in his bed as he stroked her hair, a quiet wedding ceremony on some distant planet with only themselves in attendance, a little Time Lord with his messy hair and Rose's eyes.

Even though he knew it was an illusion, the Infinite's power only sufficient enough to produce an echo, he let himself savor it for a moment. For just one moment he was with her again. But this had to stop, and he knew it. He knew if he let this illusion Rose speak, just for a second, he would be lost in the sound of her voice. He would drown himself in her every tone and lilt, and he would never be able to break free. With a huge effort, that felt like the breaking of his hearts all over again. He turned away from the image.

"Oh, don't even try to find my heart's desire" The Doctor advised the Infinite, quietly. He was suddenly angry, so very angry. How dare this ancient piece of space junk taunt him with what he most wanted, but could never have? Wasn't it bad enough that he must be forever separated from her, without having her image before him? He could feel the blue light shining behind him, and it took all the willpower of his 900 years not to turn around and embrace it.

So instead, he turned to Martha.

"Hello, you. Proper you" Martha said with a grin. The Doctor pulled her into his arms, giving her a hug. Considering what he had just seen, it was probably not the best idea, but as he squeezed her to him for a moment, he felt the anger of a few moments ago drain away. Martha was good for him, after all.

He pulled away, hiding his turmoil and aching hearts behind a mask of cheerfulness. After all, he hadn't seen Martha in quite a while.

"Now then, aren't you going to ask me how I got here?" he asked, flashing her a trademark manic grin, "Hear all about my adventures on Volagnock? How I bottle fed Squalk with molten gold and reprogrammed Lock to run a better prison? It's been 3 years you know"

"Three years?" She sounded shocked. He shrugged. He was over 900 years old, so three years was hardly anything compared to that.

Three years was all you had with Rose that nasty little voice inside of him threw back. But that had been different, he assured himself. Three years fixing Squark and reprogramming Lock had not seemed so bad. Three years with Rose had been a blissful eternity that flew by all too quickly.

"Well, two and three quarters. We gained a bit of that back by flying past light speed, of course" He remarked, trying to sound offhand.

"Light speed? How?" gaped Martha. Sometimes, she was too easily impressed. The Doctor had to remind himself that she hadn't been doing this space travel thing for very long. She was still new at it.

"I gave Squark's engines a bit of pep. A bit of zing. A bit of…."

"Va-va-voom?" Martha broke in with a giggle. Then, "I knew you'd be back." She glanced around her at the huge cavern that comprised the inside of the ship, "So, this is the Infinite" she said, awed.

"Every pirate, treasure hunter and freebooter would want to find this" The Doctor said, hoping that she would not ask the obvious question, the one that he knew was inevitable. He had seen her heart's desire. She would feel she was entitled to know his in return. But it doesn't work like that, Martha Jones.

"You're heart's desire…. What did it show you, by the way?" There, she had asked it. He couldn't say he was surprised. She was a human, after all, and they were a curious species. He hid behind his mask, not letting his true emotions slip out, not letting her see that being this close to his Rose, even a Rose that was an illusion, was breaking his hearts all over again.

"Doesn't matter, it didn't work on me" he lied, and changed the subject hurriedly.

As they rushed back to the TARDIS, the Doctor looked back, one final time. She was standing there, his beautiful, wonderful Rose, and it took everything he had not to rush back into her arms. So the Infinite was about to blow up, so what? It would have been worth it, if it had really been her. As he threw one last longing glance over his shoulder, he saw the illusion Rose smile at him, that soft, radiant, teasing smile that he loved and would always cherish in memory. Maybe seeing her one last time hadn't been so bad after all.