"Doctor! "

The Doctor turned, one foot inside the TARDIS, the other still in the forest mud. A Na'vi was running toward him, taking yard-long strides across the forest floor. He could have easily been the subject of a photograph from National Geographic, if he hadn't been wearing a pristine white labcoat over his lanky blue body.

The Doctor realized he recognized him. "You're Jake, aren't you?

"Not quite," he replied, crouching down to match the Doctor's height. "You've not got an avatar yet, have you?

"No, just getting it, but-"

"This is yours," he said, pulling out a sonic screwdriver and giving it to the Doctor. "Don't use it until you know where it comes from, the second time around and don't look at the contents, again 'till you know where it comes from, oh and Doctor", he paused, and inhaled, "thank you."

"For what? What's on this?" the Doctor said.

"Remember what happened the last time you gave someone your screwdriver. Will happen. You know what I mean."

The Doctor remembered, but only looked at the alien, shocked.

"What happens the second time?"

"Spoilers," the scientist said, before running off.

—

Grace weaved through the crowd of workers before arriving near a young man in a white shirt, who was playing mini-golf into a mug.

"Parker, we need to talk," she said.

"Hello, Grace," he replied without taking his eyes off the golf. "Go on, talk."

"You know what's out there, don't you?"

Parker didn't respond for a few seconds, and instead concentrated on putting his golf ball. As he hit the ball, Grace kicked the mug over. "Oops", she said as Parker glared at her.

"We've been through this," he said.

"And they're still out there, getting stepped on, or run over, or shot, or..."

"Come with me," he said, frustrated, weaving his way through the busy control room to a door on the far side.

"Do you even know what's out there?" Grace said, as he unlocked the door into his office.

"I don't ca―"

"Hello, Mr. Selfridge!" said the Doctor from leather chair on the far side of the room. For almost a full second Selfridge looked at the Doctor, dumbfounded, before glancing at the door he had just opened.

"That door was locked..."

"Well, yees, but I've never let a door stop me finding something interesting, and this place is pretty cutting edge for being built in the 2140s, it's even got the synthetic leather, and I'm sorry for being so rude, would you like a jelly baby?" the Doctor said, offering a brown paper bag. It didn't seem to come from anywhere; it was merely not there one moment and being unfolded in the next.

Grace causally took one and chewed it while Selfridge just stammered "Who are you?"

"I'm the Doctor," said he.

"These are nice," said Grace, "when did you say they came from?"

"1958, straight from the factory."

"I... you're mad! Both of you!"

"We've been through that too," Grace replied caustically. "Besides, he knows."

"What?" said Selfridge, rapidly losing track of the conversation.

"I'm the mad man with a box," the Doctor said, smiling innocently.

There was a pause, before Selfridge said, trying to stay calm, "What do you want?"

"Just wondering what all the arm-wavy stomping military set-up's about, since you'd be pretty mad to be using this place as an actual garrison, unless... no, that doesn't appear for another century at least..."

"We're mining unobtanium," Selfridge hesitantly explained. Suddenly, the Doctor reached into his pocket, with a vague, "What...?" He kept searching for a moment, before burying his entire forearm into a pocket no more than two inches across. "This stuff?" he said, pulling out a silver rock clearly larger than the pocket he had just taken it from.

"That...stuff..." Selfridge squeaked. "...How?"

"Why would you be mining it? I mean, you can synthesize it out of mud, water and..." he stopped suddenly. "You can't synthesize it, can you? That's the next decade, isn't it? Sorry for confusing you, I'm not used to doing this kind of thing in the right ord-"

"It's worth twenty million dollars a kilo! " said Selfridge, clinging to what he knew in the onslaught of absurdity.

"Oh," said the Doctor, suddenly deadly serious. "Why are these sorts of things never easy to fix?" he turned to Grace. "You never just here for science, are you? You-" Suddenly, the phone rang. Equally suddenly, it was by his ear and he began telling it, "Sorry, Mr. Selfridge isn't- Oh." There was an ominous pause. Selfridge and Grace exchanged glares. "Norm, can you say that again for Grace and Parker here?" the Doctor said, flicking a switch.

"Jake's cloned himself," Norm's voice said.

Selfridge and Grace looked away from each other. "I haven't touched him!" objected the Doctor.

—

Jake dug his toes into the dirt, and for a moment, stood there, drinking the new sensations that flooded him. A noise behind him made him turn, still revelling in the feeling of his tail swinging behind him and the dirt between his toes. He saw a bush nearby shake, before a figure suddenly leapt out of it, and rugby-tackled him to the ground. He looked up and found... himself in a lab coat and t-shirt.

"Having fun?" the stranger said, grinning.

"Who are you?" Jake replied.

Suddenly, the stranger looked worried, and glanced back to the bush. "Well, you know that the Doctor's a time-traveler, right?"

Jake raised his new eyebrow. "Right..."

"If you could change one thing in history, however minor, would what it be?"

...Nothing," Jake replied after some hesitation.

The stranger looked dejected. "Well, thanks," he said sarcastically, while he fished a wallet out of his coat and flipped it open.

"But— you— what?" said Jake.

"Just wait for the Doctor, OK? Sorry, I forgot this wasn't easy to follow."

The Doctor arrived a few minutes later, Grace following him. She was remarkably unfazed as he walked out into the forest with neither respirator or avatar, telling the concerned Norm, "He seems to know what he's doing."

As he approached the two, he said, "Right, I've met you, you're Jake, who are you?"

"Spoiler," not-Jake replied quickly.

The Doctor paused. "...How many times have you met me before now?"

"Once."

"Jake, been meaning to ask," the Doctor said, ignoring the tangent, "why are you here? Everyone else here is high-end biology or psych research and I heard you dissected a frog once."

"Brother was training for this, but he was killed for his wallet, so they pulled me in instead."

"Ah!" the Doctor said, suddenly delighted. "When? Down to the day!"

"Er...6th May, 2148," said Jake, surprised at the question. He looked back at not-Jake, who winked at him.

The Doctor, ecstatic, started running back to the building. He didn't notice the two clones exchange smiles. "Amy! Rory! Back to the TARDIS! Let's get you fitted!"

Eventually, with its slow, metallic grinding, the TARDIS left the room.

The Doctor stepped out from the forest, tall and blue, and said, "Sorry about that. We ended up arriving ten minutes earlier than we left, and paradoxes aren't allowed. By the way, nice job with not letting on, Tom."

—

2148

Dr. Sullivan walked quickly through the dim street. He wasn't afraid, as such, but certainly had far better things to do than hang around in the streets, especially at this time of night. As he passed an ally-way, a young, bright, out-of-place voice said, "Thomas Sullivan?" He froze. "Yes?" he replied.

Someone detached themselves from the shadows of the alley, and sidled behind him. "I'm sorry about this, really, but it's important. I know it's difficult, but, please..."

The shock of cold metal suddenly ran through him, and he realized the stranger had just back-stabbed him. He felt his own blood, disturbingly warm and sticky, leak out of the wound and ooze around his back, and tried to say something and object. His lungs failed him, and he simply collapsed forward.

The stranger behind him hadn't moved from his position, only withdrawn the knife from Tom's rapidly failing body. Darkness seemed to creep around the edge of his vision, and as he slipped out of consciousness, the last thing he heard was a mechanical whirring sound by his ear.

He woke up surrounded by brass and cogwheels and mechanisms. He realized that there was a young man, in a suit and bowtie, standing beside him. He groaned in drowsiness, and the man spun around and crouched down beside him. "Oh, good, that would've gone horribly if you didn't wake up..."

With the efficiency of a bullet through treacle, Tom Sullivan managed to process what had just happened to him. He recognized that voice.

"You stabbed me! " he said, both in surprise and alarm. Second thoughts flashed through his brain, and he looked down towards his chest. It was blue, mottled with turquoise and white stripes. He simply stared at it. He knew exactly what it was, and still didn't believe it.

"Yes, but look what you got out of it," said the man in the bowtie. "By the way, this is yours," he continued, handing over a leather wallet. "As I said, it's important. Trust me, I'm the Doctor."