All characters are the property of their respective creators - David Shore, Sydney Newman, Donald Wilson, Bryan Singer, and probably many others I am not aware of. Please don't sue me.
Date and Time irrelevant
"Doctor Shaw!" The Doctor grinned widely. "What are you doing in here?"
Liz smiled. "For almost a solid year I worked alongside you, Doctor, and never believed your stories that this old box could fly. Now's your chance to prove it."
"You do realize, do you not, that our next stop is one hundred forty million years in the past?" The Doctor threw a lever, and the column at the center of the control unit began to move. The grinding, wheezing sound of the TARDIS' engines filled the control room.
Liz shrugged. "Bit late to change my mind now."
House cleared his throat. "So do we actually have a plan?"
The Doctor looked offended. "Plan? Why would we need one of them?"
House rolled his eyes. "Okay. You said something about Cybermen."
"Yes," said the Doctor. "But I also said that they would be unlikely to use bionanotechnology. They prefer their technology to be completely inorganic."
"Have they ever used nanites to mimic a disease before?"
"No," admitted the Doctor. "They did once use their Cybermats to fake a plague. But that was a distraction from their main goal."
"What bad guys have you encountered who would use such a thing?"
"Again, you're assuming that it's being used as a weapon," said the Doctor. "Aliens don't always try to conquer Earth, you know."
"Let's assume that they are trying that this time. Who would use these?"
"Well..." The Doctor frowned. "The Daleks could, but they're not normally this subtle. They have the ability, but they prefer to simply blast problems. The Cybermen are more than capable of this subtlety, but bionanites are not their style. Sontarans hold it as an article of faith that battle should be face-to-face. They've got the ability to do this, but would scorn it as cowardly."
"You're just listing off the people who wouldn't do this," snapped House. "This isn't helping!"
"Sorry. It's just the way I think. Now, the Rutans." The Doctor brightened. "They have the ability, and the mindset. But I've only dealt with the Rutans once."
"How did that go?" asked Liz.
"Well, I won." The Doctor shrugged. "Had to convert a lighthouse into a laser cannon, but I won."
House shook his head, a smile pulling at his lips. "So how long until we get...wherever we're going?"
"Time is irrelevant, here."
"Maybe to you. But I'm getting bored."
"Bored?" The Doctor looked scandalized. "Here you are, in a time capsule that is light-years ahead of your current technology, in the presence of an alien being, and you're bored?"
"It's the alien who's boring me. How long?"
"Two minutes more, perhaps." The Doctor looked down at the instruments. "Yes, almost at the end of the chronon trace."
"Great," mused House. "Then we can...?"
"I told you," snapped the Doctor. "Until we know what we're dealing with, there's no way to make plans." He grabbed a control and pulled it, and the grinding, wheezing sound of the dematerialization circuits began. "Sixty seconds to touchdown."
The door opened, and the Doctor stepped out into a forest. He looked around, frowning slightly. "This looks like Earth, about seventy million years ago."
House and Liz stepped out after him. "I'll have to take your word for it, since I'm not trained in operation of a flying saucer. Or a flying phone booth." He looked at the trees with interest.
Liz, on the other hand, appeared to be in shock. "It really does fly. I can't believe it."
"Well, I told you."
"What part of Earth is this?"
"According to the TARDIS' locator, we are about a kilometer west and north of Carnegie Lake."
"In other words, we're at the hospital," said House. "They just haven't finished building it yet." He knelt painfully, and ran his hands through the plants around them. "This looks like just plain old grass."
"It is the most common ancestor of modern grass - the so-called 'true grasses,'" said the Doctor. "This time period would be the earliest that grass appeared."
"You are a bottomless font of useless information," said House. He plucked a few handfuls of the grass and tucked it into his pocket. "I've got a friend who'd want to take a look at this."
"I find that difficult to believe." The Doctor pulled his chronon tracer from a pocket and consulted it. "We're not too far off from the source of the eddy. Perhaps half a kilometer. We should be able to walk that in ten minutes." He glanced down at House's leg. "Or perhaps thirty."
"No picking on the cripple." House stood up slowly, and pulled his pill bottle from his jacket pocket. "One of these, and I should be able to keep up. Or at least, we can do it in twenty."
"A pyramid?" House frowned. "That's about the last thing I'd expect to see here."
"Why? Surely you realized that they are not found solely in Egypt."
"Yeah, that I knew," said House. "But you don't need to be a Time Lord to realize that there were no humans on Earth seventy million years ago. Who built the damn thing?"
"You see, that's where you went wrong," said the Doctor. "Just because it's a pyramid on Earth, it does not follow that humans built it."
"Aliens?" asked Liz. "Or perhaps an earlier native intelligence, one that didn't survive?"
"Given the presence of bionanomachines, I would think it would be aliens," said the Doctor.
"That depends," pointed out House. "What if the pre-human civilization was much more advanced than ours?"
"If that were the case," said the Doctor testily, "I am certain that you would have found artifacts left over from that civilization. Are you deliberately trying to annoy me?"
House shrugged. "Is it working?"
The Doctor scowled, then glanced back at the pyramid. "Still, one would think that, since we're only a few miles from the hospital's future location, you might have noticed something like this. At least the foundation would have survived."
"Not neccessarily," said Liz. "While it's true that the foundations of a building can last a very long time, we're still talking about a hundred and forty million years. Plus, there were humans living on this continent for ten millenium before white man came along."
"True," conceded the Doctor. "But the native humans of this continent were stone-age, and I doubt they'd have the means, or the interest, to dismantle that pyramid."
House pointed his cane at the pyramid. "So why don't we drop in and say hello? Have a cup of tea. I know you Brits like tea. Do Rutans like tea?"
"We still don't know that it's Rutans," said the Doctor. "They just seem the most likely to be responsible."
The voice had an odd, resonant tone to it. The three Doctors turned slowly, and raised their hands.
Facing them were five beings. Their appearance reminded House of a four-month fetus, but with rows of suckers along their heads and appendages. Four of them had weapons of some sort, pointed at them.
"Ah," said the Doctor. "I'd somehow forgotten about them."
"About what?" asked House.