AN: I read this beautiful Doomsday fix-it oneshot called Time in a Bottle by Vampiyaa, and I just had to write my own fix-it fic for it. Can't believe I haven't thought about it earlier.

The oneshot, in case you'd like to read it (and you should): s/10946173/1/Time-In-A-Bottle

Part One: His Impossible Girl

As the Doctor sat on his chair in his porch on Trezalore, he found himself thinking about the past.

Or rather, his past.

There were so many people he'd lost along the way. Too many. So many of them he couldn't have saved, even if somebody would have warned him he was going to lose them. Amy and Rory, for one; even if he'd have read the book to the end, they were too deeply within the paradox to be able to stop it. And then there was Donna Noble, but he couldn't have saved her, either, not when their timelines were woven together so closely, because she was, after all, born to save him.

And then there was his Rose.

It's been over a thousand years since the last time he saw her, but in his mind she was still his Rose. His beautiful Rose Tyler, who was taken away from him in Canary Wharf. His Rose Tyler, whom he'd sent back to the alternate universe, to live with his human, meta-crisis self. His Rose Tyler, who was probably dead by now, but in his mind was still twenty-two, just like the last time he saw her.

Could he have saved her?

The second time around, he could have. He knew it. After all, he was the one to have given up on her, to have left her. She wasn't taken away. He could have kept her with him in the TARDIS, like they both wanted, until she'd have died in his arms. It was his choice to leave her behind.

But the first time around… could he have saved her?

His younger self spent years thinking about that. In his mind he explored every possibility, every timeline in which he didn't lose her. He considered going back in time and warning himself of Torchwood; going back and stopping Queen Victoria from ever creating it; even burning up the universe to pull Rose back to him from the alternate universe. The universe was, after all, meaningless without her.

He straightened up in his chair. Was that what Clara meant earlier, when she asked him to think about himself, for once?

He had to dismiss the idea. Clara may have been to his entire timeline, but she couldn't remember anything. Even his Time Lord consciousness couldn't keep track of everything he's gone through in those hundreds of years; Clara's human mind most certainly couldn't. And yet, there was something about the way she said it that made him wonder whether she remembered how important Rose was to him.

Thinking back, the Doctor tried to locate all the Claras he'd met. The first one was the one who told him to take this TARDIS, rather than a functioning one (The TARDIS sent him an angry wave and he quickly apologised in his mind). Then she was there the first time he and Susan landed on Earth, but he didn't even notice her. In growing wonder, the Doctor slowly listed all the times he'd seen her before but never noticed her, realising just how important she really was. Truly, he'd never have survived without her.

He froze when he realised she was in Canary Wharf that day.

A few seconds later, he was running down the stairs to find Clara. Being him, he ended up falling over the last couple of stairs and landing on the floor – and didn't that hurt – but he hurried to get up and find his companion.

"Clara." He shook her shoulder gently, trying to wake her up.

"Go away," She mumbled, rolling away from him.

"Clara, wake up."

"Let me sleep," She mumbled sleepily, again trying to shake him off of her.

"It's important," He tried, again shaking her. She groaned and tried to push him away, but eventually, when she realised he wouldn't stop, she sat up and opened her eyes, glaring at him.

"What?" She asked, and if looks could kill the Doctor could have sworn he'd have been dead by the time she finished asking the question.

"You were in Canary Wharf." His voice was quiet. "Do you remember?"

She blinked in surprise. "What do you mean?"

He almost sighed, but stopped himself in the last moment, knowing she wouldn't like it. "Do you remember the ghosts in London?"

She nodded slowly. It seemed that between her surprise and confusion she forgot he woke her up. "Of course I do. But they weren't really ghosts. They were Cybermen, weren't they?"

He nodded. "Yes, they were. But do you remember where you were that day?"

She frowned as she tried to remember. "I was probably working," She said eventually, after a long silence. "Maybe in the Maitland's house. Why?"

"You were in Canary Wharf." He looked at her intently, as if he was trying to bring up the memories with his eyes. "Don't you remember?"

She shook her head. "Why would I be in Canary Wharf?"

Trying desperately not to show the pain he was feeling, he replied, "Because that's when I'd lost Rose."

She looked at him quietly, slowly understanding what he was implying. "Maybe," She said eventually. "But I can't remember most of it. Do you think I was there to save her?"

"I don't know." He sighed and then sat down on the floor next to her. "Earlier, when you said I should start thinking about myself, I thought maybe you were talking about saving Rose, but…" He looked away for a moment before forcing a smile. "An old man's wishful thinking, perhaps. Go back to sleep."

He started getting up, but to his surprise, she stopped him. "Do you think I could have saved her?" She asked quietly.

"I don't know," He admitted. "Sometimes I think I could have saved her." His eyes became somewhat distant as he thought about losing her. "Maybe nobody could. Maybe it really is just wishful thinking. And maybe if I'd have just noticed you back in Canary Wharf, I could have saved her."

"Then isn't it worth a shot?" She asked softly, surprising him.

"What do you mean?"

"If there's a chance we could save Rose…" She hesitated briefly, biting her lower lip in an uncharacteristic sign of doubt, "Shouldn't we try?"

He stared at her, still not quite sure he knows what she means. "I can't change my past," He said slowly, reminding her that even he had to bow to the laws of time.

"Then how did you save Gallifrey?"

"I…" His eyes found hers and he smiled as a new idea came to his mind. "All I need is the right message."

She returned him a smile. "One would think so."

He laughed quietly. "One certainly would."