The Doctor steps out of the TARDIS, clearly on Earth, into a small, sort of dirty alley. He looks at his watch.

“Earth! London! 21st century! May 11th, 2020, to be exact.” The Doctor puts a hand on his TARDIS, “But why here? Why did you bring me here? Everything’s f-”

BOOM!

The Doctor spins around and runs out of the alley. There are Dalek ships in the air and a block of Daleks is coming down the street towards the Doctor. There are no humans to be seen.

“What!”

The Doctor is spinning around, trying to absorb it all. The Daleks see him.

“You have exited your home. Return or you will be exterminated!”
“How!? This doesn't happen! How could you have invaded?!”
“Daleks do not answer humans. Return or you will be exterminated!”
“You answer to me! I am the Doctor… and you don’t remember me. Right.
“You defy the Daleks. You must be exterminated!”
The doctor hears a shout from behind him, “DUCK!”

The Doctor spins around to see a girl holding a very large gun. It is obviously extra-terrestrial. He jumps out of the ways, and she fires. She shoots all the Daleks, powers down her gun, and walks toward the Doctor. She is tall, with shoulder length, blonde hair and green eyes. She looks about 16. She has a dark blue shoulder bag. TARDIS blue.

“Standing out there in the open is a guaranteed way to get shot. You better get inside.”
“How? But, but … how? The Daleks aren't supposed to be here. They all got wiped out! Gone! How long have they been here.”
“What, you been living under a rock? ‘Bout a year. Hard to say exactly. They took out all power sources when they first came.”
“Then how do you have a gun? And that gun, it shouldn’t even be here. It’s way ahead of its time.”
“And Daleks aren't? Speaking of which...”

The girl pulls out what looks like a GPS. She looks at it for a minute, then put it back in her bag.

“There are more coming. I gotta go. Either come with me or find your own way, but don’t stay here.”
“You can track them?! How?! Who ARE you?
“Name’s Jay. If you’re not coming then I’m gonna go. I don’t wanna die.”

She turns and walks into the alley. The Doctor runs after her.

“Wait up!
“Decided to live, have we? Come on then, follow me.”

They walk through a winding maze of backstreets and alleyways. The Doctor questions Jay, trying to find out more about her.

“But where did you get that technology? You are human, right?”

He pulls out his sonic screwdriver and scans her. Jay’s mouth drops open. She stares at the screwdriver.

“Yep, definitely human.”
“Where did you get that?!”
“I built it. It’s my sonic screwdriver.”
“But… but… that means… no, it can’t be.”
“What can’t be? What’s so important about my screwdriver?”

Jay swallows and composes herself. She turns around and keeps walking, obviously hiding something.

“Nothing. It means nothing. We’re almost there. Just out of curiosity, what’s your name?”

“I’m the Doctor.”

Jay fingers a key hanging around her neck. “Knew it!”
“How much longer? My feet hurt.”
“Baby. Well, we’re here anyway.”

She drops the key under her shirt. Walking up to a manhole, she pulls a crowbar out of her bag.

“How did it fit in there?”
“It’s bigger on the inside.” Jay replied, a small smile on her face.

She pries open the manhole cover.

“After you.”
“Down there. In the sewer. You are kidding, right?”
“Nope.”

She pushes him down the hole. He shuts his eyes, screaming.

“AHHHHHHHHHHhhhhh… oh. Ehem. Right. Gravity platform.” He straightens his bow tie. “I knew that.”

He looks around as they go down.

“Where did you get this!? How can a human in the 21st century have a gravity platform, a laser gun, and a Dalek tracker?! It just isn't possible!”

“I didn't get them, I built them.”
“Built them?! How?! Humans have never seen anything like this before. Not to mention it’s impossible to get the parts on this planet.”

They reached the bottom of the tunnel. She reached into her bag and pulled out a gravity globe. Again, the Doctor looked at her with a gaping mouth.

“That isn't invented for...” He checks his watch, “...368 years!
“Well, I invented it 4 months ago, so obviously your history’s a bit off.”
“My history is perfectly fine, thank you very much!”
“Keep telling yourself that.”

She threw the gravity globe in the air, then walked off down the tunnel. The Doctor followed, deep in thought. They walked through tunnels, the gravity globe lighting the way. Eventually they got to the end of the tunnel. It led into a big underground room with at least 30 tunnels leading to it. It had been converted into a refugee camp. Jay walked through, passing out food and technology that she kept pulling out of her bag. The Doctor’s eyes widened with every object she pulled out.

“How does that all fit in there?!”
“Oh, you of all people shouldn't be surprised.”
“What’s that supposed to mean. I only met you 30 minutes ago.”
“41, actually.”

She walked into the biggest tent, and the Doctor followed.