Ten stepped forward; he had a promise to keep. He pulled her into his arms, and just held on tight for a few seconds. He knew that Donna would want to hug her, and that this had been hard on her as well, but the Doctor hadn't had any opportunity to hug his little girl.
He hadn't been trying to have a baby with a Donna when she had started to date John Smith, and he never even really considered the possibility. And then she called him with the news, and he had known that all he could do was tell her what had happened.
He remembered sitting at the kitchen table and could hear her inside his mind, starting to burn. He told her everything, and was thankful when she begged for him to take it all away again. He would have done it anyway, he wouldn't let her or his child burn, but this way it was her choice.
It meant that he couldn't ever even say hello again, but he had been around. He had come by as often as he could, and saw Emily growing up. He had touched her life as much as he could have without it being enough to make her or her mum question.
It wasn't the same as getting to hold her, or sing her lullabies, but it was the best that he could do. This way she could have a normal safe life, with her mum and she would be fine. The last thing he had done, while Donna was still asleep, was give her an injection.
She couldn't very well have a child with two hearts, so he time locked his little girl's genes. Right now he could feel that second heart beating against his chest, and it brought tears to his eyes.
He forced himself to let her go, and Donna swooped in, pulling her close to her.
Emily was smiling over her mother's shoulder, and eventually they had all taken a turn at hugging her.
He had heard Nine whisper that he loved her again, and it made him smile.
This man was the one before Rose, who had done him a world of good. He would have to go back to his TARDIS and lock these memories, but in two days he would meet Rose, and they would start their journey.
It would be one that would cost him a body, and cause him a lot of pain, but sometimes that was how we learned what mattered.
Back then it had been only Rose. Time would change that, but the Doctor still had that too look forward to.
He had all that time with Donna, which would have never been enough, but now he had them both.
And then there was his next body, which had lost both Rose and Donna, and now he had River. People came and went in his life, and sometimes it was hard to even bear it, but they never ever took away the ones he had held dear.
They would be with him forever, no matter the body.
"What happened?" Emily asked.
Ten looked at Donna who told him plainly, "You are explaining."
Ten nodded, and decided it was best to do it in private. He took his daughters hand, and led her to the kitchen where they sat.
And explain he did, everything that she could possible need to know, and she watched him carefully. She looked him over in that same way her mother had, always seeing everything he wasn't saying.
Finally he was done, and she simply nodded. This would take time to get used to, and there would have to be decisions made. What would Donna and Emily do now, and would Eleven make them welcome in his TARDIS? They couldn't go with Nine, and he knew that his time was closing to an end.
The man in the other room was proof of that. He would never change, never leave if it could be helped, but it couldn't. He longed desperately to stay a while though. Get to know the girl he had only known from a distance, and love them both fiercely, until he couldn't outrun fate any longer.
When he had to change, he wanted them to know that he couldn't have loved them anymore, and that they were his, always.
DW
The Doctor waited in the room with Nine and River, and they were talking, leaving him time to think. Nine had to go home; he had a blond to meet soon. But what could he do with Emily and Donna? There was no chance he was leaving them back on Earth unless they made him, but he would have to talk it over with River.
She would have to go back to prison at some point, to make an appearance, and it would be nice to have someone to travel with in her absence.
He still couldn't believe it. He had a daughter, a girl who carried his genes into a new generation. He had so much he wanted to teach her, show her, and he longed to see Donnas' reaction to the universe all over again.
It was safe to say he still loved her, but he was a man who understood duty. And he had made River a promise and he wasn't going to break that promise. Even if it hurt.
The door opened and Ten and Emily walked back into the room.
It was time for Nine to go, and the Doctor led them all to the console room. The Doctor flew them to where they had left his TARDIS and they said their goodbye. He said goodbye to Emily last, and though the Doctor couldn't hear the words he saw tears run from Emily's eyes.
Nine swallowed hard, and he kissed Emily on her forehead leaning back and saying, "Promise me?"
"I promise," Emily said.
He kissed her head again, and then walked out of their lives.
He would be fine, the Doctor knew, but for a few moments he was going to hurt like hell.
The Doctor felt more weary then he had in so long, and he really wanted to sleep. Emily was looking at the ground, and though the Doctor knew that it was explained to her, it was hard to find out your whole world was different then you thought.
She would need time to adjust to this new point of view, but she wasn't alone. Ten could stay as long as he wanted, until it was finally time for him to go, and then they would go from there. He deserved the chance to see his child, and the woman he had loved more than any other.
The time was coming, but it didn't have to come yet.
He looked at the group, slightly mismatched, another version of himself, but it was a family all the same. He reached for a lever. He didn't know what was going to come, but they wouldn't leave anyone behind.
They were all safe in the TARDIS, and for this moment, they were all home.