"What's wrong?" the Doctor asked, as he and Rose entered the TARDIS.
"Nothing," Rose muttered glumly.
The Doctor remained silent as he walked over to the console.
"It's just..." Rose continued, letting the sentence trail off as she sat down with a sigh.
The Doctor absently fiddled with some of the controls, still saying nothing.
"Why did you have to bring him along?" Rose finally blurted out.
"Who? Mickey?" the Doctor said, "Because he asked. Besides, I thought you'd be pleased."
"I guess I am, sort of," Rose replied, "I just liked things better the way they were."
"Him just waiting at home for you, you mean?"
"Well, not when you say it like that," Rose said, frowning, "It's just all different now, that's all."
"I'm different," the Doctor said, half-way between a question and a statement.
"Yeah, but not just that," Rose said, "There's Sarah Jane, and now Mikey... I'd just like for at least some things to stay the way they were."
"Everything changes, Rose," the Doctor said softly, "It's the way of the Universe."
"I know."
"I can take him back though, if you want," the Doctor offered, "Tell him I've changed my mind."
"No," Rose shook her head, "That wouldn't be right."
"No, it wouldn't," the Doctor agreed, "And he does seem to be enjoying himself."
"Yeah, he does, doesn't he?" Rose said, smiling slightly.
The Doctor returned the smile.
"You sure he's all right out there, on his own?" Rose asked, gently shifting the conversation.
"He'll be fine," the Doctor said, "It's just a Bazaar. I'm sure it's perfectly safe-- well, probably perfectly safe-- well, if he gets into trouble, he knows where the TARDIS is."
"Way to reassure me," Rose teased.
"I think it'll do him good to roam the market a bit, without us," the Doctor said, "Give him a chance to feel like a real explorer."
"If you're sure."
"I'm sure," the Doctor said, "And while we wait, I'm going to go put this away." He held up a small leather-bound volume that he'd obtained from one of the vendors.
"You bought a book?" Rose asked.
"I bought a book."
"How?" Rose asked, "You're rubbish with money."
"I had some bits of currency from here and there," the Doctor replied, "I just put it all on the counter, and the vendor picked out what he needed."
"How do you know you didn't get cheated?"
The Doctor shrugged. "I got my book."
"The TARDIS has a library?" Rose asked, as they walked down one of the many corridors that riddled its interior.
"Of course," the Doctor answered, pausing momentarily at an intersection.
"Why haven't we ever been there before?"
"What?" the Doctor said, confused, "I've been there lots of times."
"I mean why haven't I ever been there?" Rose clarified.
"Oh," the Doctor said, as they turned another corner, "I don't know. I guess we just never..." He stopped at a doorway. "Ah, here it is!"
Rose followed him into the room, which was at least twice the size of the console room, with shelves of books covering every wall.
Other than bookshelves, the only furniture in the room was several large, overstuffed chairs, a couple of small tables, and a tall, wheeled ladder on a track that ran around the entire room.
"Look around, if you like," the Doctor said, "I'm going to find a home for this." He gently tapped the cover of his new book, and then took his glasses from his pocket and put them on.
Rose sat down in one of the chairs, and watched as the Doctor wandered along the shelves, periodically pulling out a book, and flipping through the pages, before putting back.
"I've been meaning to ask," Rose said, "Why the glasses? You never needed them before."
"What?" the Doctor said, looking up from the book he was holding, "These?" He pointed to his glasses. "It's the eyes. They're just a bit hyperopic, since I regenerated. Nothing serious."
"Regenerating damaged your eyes?"
"Damaged them?" the Doctor said, "No. They're as good as new-- well, they are new actually. They're just not quite the same as the old ones."
"Oh," Rose said, still not really clear on how the whole regeneration thing really worked. As the Doctor continued his search, she looked around the room again. Most of the tables were empty, but there was a large book lying on the one beside her, and it had an intricate, swirling design on the cover.
She opened it, not sure what she was expecting, but was surprised to find that it was filled with what appeared to be wedding photographs. Her eyes were immediately drawn to one image of a distinguished, middle-aged man. He was in several pictures, but in this particular one, he appeared to be dancing, with an expression of unbridled joy spread across his face.
"That was quite a wedding," the Doctor said, startling her slightly. He had put away his book, and was standing behind her chair, looking over her shoulder.
"Who is he?" Rose asked, pointing to the man in the photograph.
"That's me," the Doctor said, "Or rather it was me, a very long time ago. That was before... everything... before I left my home world." He reached down and gently touched the page. "I actually grew old wearing that face, and that's not something that's ever happened again."
"Your planet. Does it have a name?" Rose asked, "I don't think I've ever heard you call it anything but your home world."
"Oh yes," the Doctor said quietly, "It had a name. Saying it out loud just makes it all too real somehow, so I never do." He suddenly sounded very old, and tired.
"I'm sorry," Rose said, "I didn't mean to--"
"Gallifrey," the Doctor said, in a hushed whisper.
"What?"
"My home world. It was called Gallifrey."
"Gallifrey," Rose repeated, "Good. I was afraid it was going to be something awful like Raxicoricofallapatorius or something."
"Thankfully, no," the Doctor said. He was smiling faintly, although there was still a hint of sadness in his eyes.
"So, why did you leave anyway?" she asked.
"Got bored," he stated flatly, although something about his expression said that there was a lot more to it than that. Before she could say anything, he suddenly shifted emotional gears, in a way that reminded her of the way he used to be, before he regenerated. "Ah, Mickey's back," he exclaimed, "What say we go see what he's been up to?"
"That was amazing!" Mickey said excitedly, "There were all of these people everywhere, only they were aliens."
"Funny how that happens, when you go to an alien planet," the Doctor said, teasing him gently.
"Don't mind him," Rose said, giving the Doctor a glance.
"It was just the most amazing thing I've ever seen, that's all," Mickey said, "It was... it was just... I..." His eyes fluttered wildly for a moment, and then he collapsed to the floor.
"Mickey?" Rose called out, as she knelt down beside him, "Doctor, what's wrong with him?"
"I don't know," the Doctor said, sounding concerned. He felt for Mickey's pulse and looked into both of his eyes. "He's alive," he finally said, "He's just unconscious."
"Is he in some kind of coma?" Rose asked.
"He doesn't appear to be," the Doctor said, as he connected several small suction cups to the TARDIS console and placed them against Mickey's forehead. "He seems to have simply fallen asleep."
"But why?"
"I don't know," the Doctor said, "That's what I'm trying to find out."
Rose sat beside Mickey and held his hand, trying not to plague the Doctor with questions while he was busy running tests.
"He's definitely asleep," the Doctor said, looking at the monitor, "A very deep sleep, but not a coma."
Rose stood up and walked over beside the Doctor. There was an image of Mickey's brain on the TARDIS display.
"Can we wake him up?" she asked.
The Doctor shook his head, then mumbled to himself as he typed on the console. "These levels are all wrong," he said, "Mickey Smith, what have you gotten yourself into?"
Rose hesitated, torn between going back to sit beside Mickey, and staying where she could see what was displayed on the screen, even though she had no idea what any of it actually meant.
"Of course!" the Doctor exclaimed suddenly.
"You found something?"
The Doctor nodded, still staring at the monitor. "It looks like he's been colonised."
"Colonised? You mean like an infection or parasites or something?"
"Not exactly, no," the Doctor said, "I believe what we're looking at here are Nanosapia."
"Nano?" Rose said, "Like those little machines?"
"Sort of," the Doctor said, "Only these are living beings. It appears that a colony of Nanosapia have taken up residence along the neural pathways of Mickey's brain."
"Can you get rid of them?" Rose asked.
"Get rid of them?" the Doctor exclaimed, turning to face her, "We're talking about thousands, maybe millions of life forms here. Killing them would be genocide." He turned back to the console. "Besides, they're harmless."
"If they're so harmless, why won't Mickey wake up?"
"Ah," the Doctor said, "Good point. They're normally harmless, at any rate. Something must've gone wrong in there."
He fell silent again, and began typing furiously, occasionally mumbling to himself or scratching his head.
"Oh you stupid, stupid little creatures!" he exclaimed.
"What is it?"
"They're pumping out massive amounts of sleep toxins," he replied, "They're quite literally polluting Mickey's brain."
"What? Like Global Warming?" Rose asked.
"Well, instead of climate patterns it's brain chemistry, but basically, yes," the Doctor said, "And if they keep it up, they're going to wipe out their entire civilisation."
"What about Mickey?"
"Him too," the Doctor said, "Which is basically the same thing, at this point."
"So there's a whole civilisation of tiny aliens inside his brain," Rose said, still trying to wrap her head around the whole thing, "Is there any way to get them to stop what they're doing?"
"If I could find a way to talk to them, I think so, yeah."
"Won't the TARDIS translate for you?"
"Yes, but that's not the problem," the Doctor said, "The problem is they're on a completely different timescale than we are. They've gone through many generations, since Mickey passed out.
Normally, in a case like this, I'd try to make some kind of permanent change to their landscape, something that would endure the faster passage of time... but I'd really rather avoid cutting into Mickey's brain, if at all possible."
Rose looked over at the Doctor, but his expression was unreadable.
"Maybe I could send a message in pulses," the Doctor mumbled, "Have it repeat, on a loop. That might work..."
After what seemed like several very long minutes, the Doctor finally started sending his message, by flashing lights into Mickey's eyes. "Now THAT got their attention," he said, "There's all sorts of activity going on in there. It'll take them a while to sort out my message, but eventually we should--"
There was a bleep from one of the indicators on the console.
"Clever little Nanosapia," the Doctor said, grinning broadly, "They say they got the message, and they're apologising for the delay. It seems to have started up several new religions and they had a bit of a civil war over what it meant.
Their scientists agree with my conclusions, but they're having trouble convincing everyone that the problem is really that serious."
"They understand who we are?" Rose asked.
"Not entirely," the Doctor said, "They're aware that we're aliens, and that we're on a much slower timescale, but I don't think they fully grasp the complexities of the situation." The Doctor shook his head. "Not that it matters. What's important is that they clear up those sleep toxins, before it's too late."
"Do you think they will?"
"I don't know," the Doctor admitted, "We'll just have to wait and--"
There was another bleep.
"Ah," the Doctor said, "It looks like they're doing it."
"He's going to be all right then?" Rose asked.
"I think so," the Doctor said with a smile, "The toxin levels are definitely going down now."
"What about the, uh..." Rose tapped her head.
"Nanosapia?" the Doctor asked.
"Yeah, them," Rose said, "Will they still be in there?"
"Well, yeah," the Doctor said, "But I don't think they'll cause any more trouble."
"But isn't that kind of creepy," Rose asked, "Him having these little things living inside his head?"
"Why?" the Doctor asked, looking puzzled, "You've got all sorts of microscopic organisms living in you. They're in your eyebrows, your intestines. You're practically a walking zoo."
"Gee, thanks a lot."
"Everybody is," the Doctor said, "It's part of being alive."
"Maybe," Rose said, frowning, "But this is different. You said they have a civilisation. You TALKED to them..."
The Doctor turned back to the console, with a loud sigh. "No promises, but if it bothers you that much, let me see what I can do."
He typed something else into the keyboard, and then waited until the TARDIS bleeped at him again.
"They've agreed to relocate," the Doctor said, "They're not happy about it, especially after all of the time and effort they've put into cleaning up, but they're willing to do it."
"Oh, thank you, Doctor!" Rose exclaimed.
"They're getting everything ready now," the Doctor said, "It's going to take them several generations to prepare, but it shouldn't be long, from our point of view."
There was more typing and more bleeps, and then the Doctor stepped away from the console and walked over to Mickey.
He knelt down and placed his hands against the sides of Mickey's head, gently opening using his thumbs to open his eyelids.
A gaseous stream of blue energy flowed out of Mickey and into the Doctor, causing Rose to suddenly wonder exactly where it was that they had agreed to relocate TO.
After a moment or so, he stood up, shook his head and walked back over to the console.
"They're gone," he said with a grin, "And his brain is almost back to normal-- well, normal for him anyway." He grinned again. "He should be waking up any minute now."
"Are they inside your head now?" Rose asked.
"They are," the Doctor nodded.
"And it doesn't bother you?"
"No," the Doctor replied, reaching up to touch his temple, "They should do really well in there, and they certainly don't pose any danger to me."
Rose frowned, but didn't say anything, then looked back down at Mickey. "He'll be okay now?"
"Right as rain," the Doctor said, removing the various sensors from Mickey's head, "A bit of short-term memory loss I'd imagine, but otherwise he should be just fine."
"He won't remember any of this?"
"Probably not."
"Do you think we should tell him?" Rose asked.
"What? That his brain was colonised by Nanosapia, and they almost accidentally killed him?"
"Probably not then."
"Probably not," the Doctor agreed.
Mickey stirred and then sat up, looking around with confusion.
"It's about time you woke up," the Doctor said, "I thought you were going to sleep the day away."
"I was asleep?" Mickey asked, "Did I miss anything?"
"Nah," the Doctor said, "Not really. We were just about to head out."
"Where to?" Mickey asked.
"I don't know," the Doctor said, "Let's find out, shall we?"
Mickey walked over and sat down beside Rose.
"I hope it's a space ship!"