The Doctor had quite quickly learned that he'd never understand the mystery of Rose Tyler.
He had thought that he'd understand her when he became human, because he would experience the same hormone and pheromone levels as her, experiencing symptoms and sickness and the every-day challenges that came with human life.
He was wrong.
The Doctor assumed he'd understand her when he took her as his wife, and bonded his kind with hers, so that they understood each other on a deeper level than any man and wife ever would.
He was wrong again.
Of course, he had figured out a lot of her mysteries. He knew she hated when he threw his tie on the ground and just left it there, but she loved when he wore the tie loosely around his neck, or when he let her take it off because he was distracted and tired and it thrilled her to take care of him. He knew she hated black coffee because it reminded her of home, but she loved drowning her own in creams and sugars. He knew her favorite smell was rain. He had known for quite some time that, in the few hours a week that he slept, she stayed up and "secretly" watched him. He couldn't blame her. He watched her, too. He had discovered quickly that Rose Tyler snore in her sleep, but only after a shag. "Because I'm happy," she had informed him when he told her she snores. "I sleep deeper when I'm happy."
He knew she loved sleeping on her side, so he could cuddle with her until she fell asleep. And even after she fell asleep, he held her close, reminding himself and the world that she was really his. He loved it, too, cuddling with her. She was soft, his pink and yellow human, and he felt at home when he buried his face in her hair.
But lately, she was having nightmares, and it left her restless. She ended up sleeping on her back, no matter how much she turned, and it frustrated the Doctor beyond relief. He couldn't cuddle with her shoulder very well. He had told her he could stop her nightmares, but she refused to let him, or even tell him what they were off. It was something he couldn't figure out, and she always insisted she was fine.
She was a mystery, he had quickly learned, so he didn't question his Rose when she asked him one day if the T.A.R.D.I.A.S (Time And Relative Dimension In Alternate Space) could support a garden.
"Of course," he answered immediately, before hesitating. "Well, maybe. Well, probably. It could make a greenhouse of sorts, of course, but where would the solar energy...ah! Yes, I could require the energy to create solar absorbers to suck up as much solar energy as it can and store it to use when needed. I could create a pest-control unit, too, and the greenhouse could self-water...I could increase the growing rate by ninety-six - hmm, ninety-five-point-two - percent, so that it - "
"Doctor!" Rose yelled, cutting him off. He stopped talking. "Yes, or no?"
"Yes, of course. Rose, anything for you."
They grinned foolishly at each other for a moment before the Doctor turned back to his console. He started to push a button before he realized what Rose had asked for.
"A garden?" he inquired. Rose looked sheepish, almost embarrassed, so he quickly stuffed his curiosity and changed his question. "Flower or herb?"
Rose grinned happily, relieved. "Flower," she decided.
The Doctor was impressed by Rose Tyler, he had to admit. She tended to her flower garden every day. He heard her constantly talking to the T.A.R.D.I.A.S, informing her exactly what she wanted.
She went in there constantly, weeding and watering and talking to the little seeds. Sometimes, the Doctor went in there with her; and watched her take care of the garden delicately, and gently. She nurtured her flowers, and he could tell she loved her garden.
So he never questioned why she wanted it.
"It's looking brilliant," the Doctor said one day, as Rose trimmed the out-of-control branches. In the past two weeks, the flower bushes had grown and began to bud. With Rose's care, and the T.A.R.D.I.A.S's accelerated growth support, they would have a beautiful garden shortly.
Rose beamed proudly at his comment. "I hope so," she said, looking over her garden. She found a few weeds, so she got down and began to pull at them before smoothing the dirt back down. She beamed at her work.
"It's like the bushes are your children," the Doctor mused, and Rose tensed, looking at him in surprise. "You are so gentle and nurturing to them. It's like they are your babies and you take care of them every day. Maternal instinct for flower bushes. That's a new one."
Rose swallowed and smiled. "Only you would point that out."
"Can we go back to our Earth?" Rose asked the Doctor groggily one morning, as she woke up.
"May I ask why?" the Doctor said, brushing some hair out of her face, and then leaving his hand resting on her face.
"I want to see my mum and Pete," she murmured, looking down shyly. "It's...today is an earth holiday, and I wanna give Pete something."
"Father's Day?" the Doctor guessed. Rose nodded. He kissed her nose and then climbed out of bed, grabbing his dress shirt and buttoning it up quickly. "Of course, Rose. You can ask for a present, too. The T.A.R.D.I.A.S will give it to you."
Rose nodded groggily. The Doctor kissed her gently before leaving to the console room to direct their next trip.
She came out wearing one of his dress shirts and leggings. He swallowed and turned back to the console, refusing to gawk at her. She was his wife, now, but he still felt guilty from time to time thinking of her in a suggestive way.
"Is that necessary?" he finally asked. His voice was gruff, and Rose smirked, knowing fully well what she was doing to him. She was thrilled, though, he could tell.
"Of course," she said innocently, and he shuddered. Rose grinned, her tongue poking out slightly from between her teeth.
"Mystery woman," he muttered, knowing he'd never understand why she did that to him. He twisted a few levers before turning to Rose quickly. "We'll be home in one minute, thirty-seven seconds."
"Great," she said, grabbing her trainers and a nicely wrapped present. She planted a quick kiss on his lips before slipping her trainers on.
His dress shirt wasn't huge on her, but it wasn't snug, either. He was slim, but so was she. It secretly pleased him whenever she wore his clothes, and it looked almost normal enough that most people wouldn't question it. Jackie and Pete had grown quite used to Rose showing up wearing his dress shirts, or jackets. There was once she stole his tie and wore it loosely around her own neck. He'd never admit it, but he loved her wearing his clothes. She loved it, too, and it was another mystery he couldn't figure out.
"Rose!" Jackie yelled when she opened the door and found her daughter. "Sweetheart, what are you doing here?"
"It's Father's Day," Rose said, shimmying out of her mother's hug and talking the Doctor's hand in her own. She lifted up her other hand and showed her mom the present. "Thought we'd stop by."
Rose had a lovely time seeing her family, and the Doctor enjoyed watching her smile and laugh. Tony, who was now six, climbed into the Doctor's lap and begged for stories.
He quickly diverted his attention from Rose to her younger brother, telling him stories of far-off places and beautiful species. Tony was an unusually quiet child, but he was intelligent for a six year old, and he loved hearing the Doctor's stories.
When Rose finally got tired, he took her in his arms and they said their goodbyes before leaving. He intertwined his fingers with Rose's and kissed her nose as they walked down the street, back to their ship.
She excused herself to their room when they got there, and he went straight to the console, leaving earth to wander in the stars.
It wasn't shortly after that she came back out. His dress shirt was now unbuttoned on her, revealing a tank top underneath. She hid something behind her back, and she had a devilish gleam in her eyes.
"What?" the Doctor said cautiously, and Rose grinned, poking her tongue between her teeth in the way she always did.
She stepped closer to him and then showed him what she was holding. It was a nice tie, T.A.R.D.I.S blue, and it shimmered like it held the galaxies. He took it from her questioningly.
"Happy Father's Day," she said with a shrug. He smiled slightly and pecked her, taking off his tie to replace it with his new one.
"Thank you for the tie, Rose, but Father's Day is an earthly tradition for human men who have children or grandchildren, not for husbands - "
Rose grabbed his hands, stopping him from tightening his tie. He let it hang loosely, the way she liked, and then she brought his hands down to her stomach. He touched her gently, confused, and she smiled slightly as tears filled her eyes. He started to panic, and tried to lift his hands to her face, but she forced his hands to stay on her stomach.
"Happy Father's Day," she repeated.
He looked down in wonder as he began to realize what she was saying. He stated at her stomach, and then looked up at her face, before glancing at his tie and then returning to stare at her stomach. He repeated the process several times, baffled, before he finally found the words he was looking for.
"I'm a dad!" he whooped, grabbing Rose's waist and twirling her. She laughed giddily, crying, and he quickly set her down. He kissed away her tears and then hugged her tightly before bending down. He lifted up her tank top, touching the soft skin of her stomach. It was only slightly rounded, tight and smooth. He kissed it gently, as tears filled his own eyes. "Hi, baby," he cooed. Rose choked as her emotions began to take over.
He stood back up and kissed all over her face, both of them happily crying now. "I love you," was the only thing either of them could manage to say.
And with her one announcement, all of Rose Tyler's mysteries began to make sense. But they both knew they had a bigger mystery on the way.