Note: I'm sorry I haven't posted in a long time. My computer broke down and I lost all of my files, so I REALLY, REALLY am sorry! So this is a crack!fic, and I do not own Doctor Who, BBC, or any of the actors, though some day I will meet at least one of them (preferably Karen Gillan). While writing this I was inspired by some awesome nightcore mashups. (I need a doctor- Skylar Grey, Dr. Dre and Eminem). I took it to mean I need the Doctor.

It was all an accident, honestly. It wasn't like the Doctor meant for Jack and Rose to end up as four-year-olds. It had just happened.

They were on a new planet, even the Doctor had never visited. It was gorgeous. Small ponds that were ice blue and glittered in the sunlight that washed over everything. The sky was orange, as it was nearing twilight, and made the ponds reflect the beautiful color. The trees were purple, and while it wasn't the oddest thing any of them had ever seen, it was still a sight to behold.

Jack and Rose had been walking ahead of the Doctor, laughing and talking. Every once in a while, they'd sneak glances at him over their shoulders. The Doctor scowled at them every time, knowing they were discussing him.

At one point, Jack very loudly offered Rose a piggy-back ride. She giggled and accepted. Jack hoisted her up onto his back and she squealed in delight as they swayed. Jack shot a side glance at the Doctor, smirking in a way that infuriated him very profoundly.

They came across a huge tree with a parting in the wood. It was like the trees had been stretched and bent to allow people to pass through. Jack squatted down to allow Rose to clamber off of his back. They motioned for the Doctor to join them as they headed for the mysterious tree, but he shook his head, letting them have their childish fun. He was over nine hundred years old, he wasn't going to ogle at a strange tree. He had seen much more interesting things in his travels.

That's when he noticed something. A sign was near the tree, faded and brown. He strode over to it, taking in the script which was nearly illegible. It was in the language native to this planet, but the Doctor could read it. It was a little hard to make out, but he got it in the end. It said: Beware: Tree of Youth; do not enter.

"Uh oh."

The Doctor whirled around to look at the spot where Jack and Rose had entered the tree. He hoped he wasn't too late.

The Doctor cautiously crept to the intertwined trees and looked in. Inside were two little children.

There was a little girl with blonde hair and big brown eyes. She had tears threatening to spill on the rim of them. The Doctor guessed this was Rose as a child, then. Her hair must have turned brown I the later stages of life before she dyed it.

The other kid was a little boy who looked slightly older than Rose. He had shorter brown hair and darker blue eyes. He had a quivering lip and was pouting. Jack, he supposed.

The girl, Rose, whimpered, "I-I'm cold. Where am I? I want my mum!" And the tears spilled and leaked down her face. The Doctor, still caring for Rose at such a young age scooped her up and said, "Hey, it's alright. I'm going to be your babysitter for a bit, that alright?" Rose sniffled, then nodded, her eyes still brimming with tears.

Jack started crying too. The Doctor, frowning at his own parental instincts, picked up the boy, too and asked if it was alright if they went to the TARDIS. Surprisingly, both children nodded (maybe they recognized 'TARDIS') and he started walking, holding them both a little awkwardly.

On the way back, he stumbled over roots and, embarrassingly, his own feet once or twice.

Little Rosie started shivering halfway back and the Doctor buried her deeper in him leather jacket and she snuggled against him. It was kind of odd, seeing as his body temperature was cooler than that of a human's.

When they finally reached the TARDIS, the Doctor breathed a sigh of relief. He gently lowered the two children down so they were in a sitting position. He unlocked the TARDIS door and picked up his companions once more.

"Okay, Old Girl, what do I do? My companions got themselves turned into four-year-olds, and I don't know what to do with them!" The TARDIS let out a hum that sounded like a laugh. The Doctor started walking down the hallway and came across a yellow room. It had two little beds, one pink and one blue.

He lowered little Rose into the pink one and Jack, who was asleep and drooling on his shoulder, into the blue one.

Rose sniffed and looked at him with those big eyes. He suddenly felt very protective. He walked back over to her and knelt by her new bed.

"I know you're scared, Rose, but I will take good care of you. You're being very brave. I'll make you big again, don't worry." Rose nodded and laid back on the bed. He tucked her in, and left the room.

The Doctor retreated to the library, hoping to find something on this tree of youth. He walked past rows and rows of books, all the while grumbling to himself about the TARDIS not showing him anything.

After a couple hours of searching, the Doctor was so cross with TARDIS, he kicked the nearest wall, yelling about her not helping him turn his friends back into adults. Granted, it really hurt his foot, but taking out some of his frustrations was worth it.

The TARDIS hummed unhappily, about him kicking her and their situation with Jack and Rose.

"Sorry, Old Girl, I'm just really…" and that's when he noticed someone was pulling on the sleeve of his jacket. He turned around and Rose was there, enormous eyes and all.

"Where're the toilets?" She asked, quietly. He smiled at her.

"Here, I'll take you, Rose." He held out his hand for her to take, and she did. He led her down the hallway, and found a restroom almost immediately. He stroked the wall of the TARDIS, thanking her for making this a bit easier.

Rose walked into the restroom, after letting go of the Doctor's hand of course. While he waited for her, he pondered his options. Tomorrow, relatively, he could go back to the planet they had visited earlier. He could look for someone to help him, or explore himself and find a way to fix Jack and Rose. Or, he could continue searching the library. He'd decide when the time came, but for now he had little Rose to bring back to bed.

Along the way, she yawned and asked, "Why is, no, why are you caring for me?" The Doctor stopped suddenly. He knelt down by her.

"Because, Rose, I really care for you. A lot of people do, and I promised to look after you." Rose nodded, and gave a real smile. Then she gave another shuddering yawn.

"Come on then, let's get you back to bed. Silly humans and their need for sleep." He said fondly. Rose's brow furrowed, and she asked, "But don't you need to sleep, too?"

"Yes… but not often." He answered, not looking at her.

"Why?" She questioned.

"No more questions, please. You should just go to bed and we will find a way to make you big again in the morning, okay?" She nodded, reluctantly. He brought her back to her room, or the room she shared with the sleeping (and drooling) Jack.

The Doctor helped Rose onto her bed again and she wrapped her arms around his neck and thanked him. He tucked her back in, and walked to the door.

"Always, Rose." He walked out of the room, and strode through the hallway, his hand trailing on the wall. As much as he lo- cared for older Rose, young Rose was something different and yet so similar. But he didn't like seeing Rose scared, no matter how old she was. He would find a way for her to be grown up once more.

He retired to the library, wanting to try for just a tad bit longer to find a way to… cure… Jack and Rose. Maybe 'cure' wasn't the right word, there was nothing wrong with them, but he needed his older companions back.

That was when a book fell smack dab on his head. He clutched said head and let out a frustrated grunt of pain.

"What was that for?" He yelled at the TARDIS. He scowled and rubbed his head. Then he noticed the book. It was lying open, on a page that read "Tree of Youth." He smiled.

"Thanks, Old Girl." She hummed what really sounded like, "What did you think I was going to do, you daft man?"

The Doctor picked up the book and read the page in a couple of seconds.

"It wears off after a time, depending on how long you stand under the tree." He repeated from the book. Jack and Rose weren't under for long… which meant…

He took off, skidding around corners, sprinting to the room where he had left his child companions. He reached the room and opened the door quickly, only to see fully grown Jack and Rose sitting in their respective beds. Rose's face was red, and Jack was smirking at her.

Jack stood up, the fabric of his clothes stretched too tight across his chest. "Doc, you think we could get new clothes? Rosie over there doesn't seem so pleased." The American stated, throwing a look over his shoulder at Rose, who, if possible, went even redder. Jack grinned.

The Doctor said dryly, "Go to your normal rooms, clothes will be there for you both." He could see Jack starting to ask a question, so he answered it with "no." Jack, looking disappointed walked out, looking very odd in the little clothes he had on. The Doctor looked back at Rose, still flushed, and asked, "Aren't you going too?"

"I was going to wait for you to leave." She answered, embarrassed. The Doctor blushed faintly.

"Right, or course. I'll just go. But, Rose, I'm glad you're back to normal." He said before he left the room. He went to the console room, waiting for his companions. Jack showed up first, finally looking a little unsure of himself.

"Thanks, Doc." He said. The Doctor frowned.

"For what?" He inquired.

"Just thanks." Then Rose made her appearance, still looking a bit red, walking uncomfortably into the room. She came up to them, and smiled, taking the Doctor's hand. He looked a bit surprised, but did not object.

"Where to now, boys?" She asked.

Jack answered, "Actually, to me it's to bed. For some reason I'm really worn out."

"I was the one who had to deal with you!" The Doctor argued. Smiling, Jack still went to his room to sleep.

"Yeah, that tree thingy really took my energy as well. You should sleep sometime, too, Doctor. Got to be ready for our next big adventure." Rose said. Then she kissed the Doctor's cheek, and with that, she left leaving the Doctor standing there utterly gob smacked, mouth gaping.

In her room, Rose beamed to herself. No regrets.

The Doctor, recovering from his shock, smiled too. He turned back toward the console, ready to set coordinates for their next destination. It would be wonderful.

After a bit, he realized how tired he was. Kids were a piece of work. But everything had been alright, and now he looked forward to his Jack and Rose's next trip together. He also was looking forwards to a next kiss, should it be.