This one is an AU set after Journey's End/The End of Time. The Doctor didn't regenerate, and Donna didn't marry Shaun. The Doctor is choosing to live as a human to be with Donna.

The Doctor could hardly believe that he was working together with Sylvia Noble, and she was being downright pleasant to him. Maybe not exactly warm and friendly, but definitely pleasant. They chatted lightly while they decorated the Christmas tree, talking about this and that as they arranged ornaments and tied on bows.

Sometimes he could hardly believe that domestic life was so easy and comfortable with Donna. He felt more at home with her than he had ever felt before. She may not remember the years when they had traveled through space and time together, but she was still just as vital to him as she had ever been. More so even, as his wife and life partner.

He had been pretending to be human for almost a year now, and he had never once regretted his decision. He would do anything to be close to Donna and have her in his life. He'd even found a way to make himself appear to age so that she wouldn't grow suspicious in a few years. Sometimes guilt niggled in the back of his mind; all of his lies and what he had taken away from her rising up to haunt him, but he pushed them away. He was terribly good at that.

"Do you think Donna will like it?" he asked, as he placed the last ornament high up on the tree and then stepped back, surveying their work.

"I think she'll love it," Sylvia said. She turned to face him, her expression serious in the low glow from the lights on the tree. "I just want you to know that I'm happy for you and Donna. I never thought I would say this, but you're a good man, and a good husband. I see how happy you make her, and the way you take care of her. I know you've both been through a lot, but I can see the love you share. I know I don't say it very often, but I appreciate you, John - Doctor, and I'm glad that you're my son-in-law."

The Doctor thought his jaw would hit the floor. "W-what?" he stammered, his eyes wide with shock.

"Oh, close your mouth. I wouldn't have said anything if I'd known you would-"

She gasped as the Doctor suddenly swooped her up into a hug, twirling her around the small living room. "I love you too, Sylvia," he enthused, grinning like a loon.

"Put me down this instant," she hissed, and he did, setting her carefully on her feet.

"What did I miss?" Donna asked, as she appeared from behind them. She looked a mess with her hair unbrushed and her nose all red, her mouth slightly open so that she could breathe. She walked across the room to him, reaching up to feel his forehead. "Are you feeling ill, John? I hope I haven't given you this cold."

"I'm fine," he assured her, as he gently pulled her into a hug, feeling sparks of her discomfort at the contact. "Sylvia and I just had a nice chat, that's all. How are you feeling?"

She shook her head, huffing a breath. "Tired and sore."

"I'm sorry," he murmured. He had hoped she would have been able to get some rest while they decorated. She had been sick for a full week, and he wished that he could take her into the TARDIS for a quick treatment to get rid of it. Unfortunately, there was no way to do that without her noticing, and so she had to suffer through it. Good thing Sylvia had offered to help decorate.

"Not your fault." She let go of him to turn to the Christmas tree, looking it up and down. "It's lovely. You've done a great job, both of you."

"We saved you the best part," he said, and nodded for Sylvia to hand Donna the star.

Donna smiled warmly as she stretched up and placed it on top of the Christmas tree, plugging it into the string of lights. It lit up a brilliant TARDIS blue, making the look complete.

"Beautiful," the Doctor whispered, but he wasn't looking at the tree.

Donna blushed when she noticed where his eyes were. "Oh, stop. I'm all sweaty and disgusting."

"You're not disgusting. Never." He wrapped his arms around her again, pulling her against him. "How would you feel about a some chamomile tea and a back massage? Maybe it will help you fall asleep."

"Sounds wonderful," Sylvia joked, and they all shared a laugh.

"It does," Donna agreed, smiling. "I love you, John."

"I love you too. Now, let's go put you to bed."