A/N Here we are again! I started working on this over the winter break after I looked through this website to find more of this type of crossover and couldn't find many. Please tell me what you think!


TARDIS

"Where are we now?" Martha asked with a huge smile on her face, the mystery of travelling with the Doctor was her favourite bit.

"National City, America, 2017," The Doctor said scratching the back of his head.

"I was expecting to see the purple seas of some exotic planet, but we ended up in America," Martha said giggling, it was enjoyable to watch the Doctor try and figure out why he couldn't pilot the TARDIS.

"It seems she has a mind of her own today. Let's go see where we landed," The Doctor said grabbing his coat off of one of the support beams and practically running towards the doors with Martha on his heels.

When they emerged from the depths of the TARDIS they were greeted with the foul smell of a back alley.

"Doctor, why do you always land in a back alley? They stink!" Martha said plugging her nose.

"Come on then Martha, let's have a look around," The Doctor said stuffing his hands back into his pockets. The smell didn't even bother him despite having a stronger sense of smell than humans.

They eagerly walked around the corner and out of the alley. A new city in a new time, Martha never got tired of seeing new locations, even if she was still pretty close to modern-day London the Doctor had a way of making her see things differently.

"Ah American cities," The Doctor began, "They all begin to look the same after a while, and smell the same. But there's something about National city that makes it special. Can't remember what..." The Doctor trailed off.

Martha was only listening to the Doctor with one ear, she was too busy looking around at all of the skyscrapers around her. This was technically 10 years in her future, it was a marvel.

Suddenly something flew overhead.

"What's that?" Martha asked as she jumped into the Doctor's arms.

The Doctor smacked his forehead, "How could I forget! That was Supergirl!"

"Would you care to elaborate?"

"Yeah. Supergirl is an alien from Krypton and she's known as the defender of National City."

"So she's an alien who flys around and defends people from what?"

"Mostly mundane things like robberies and muggings. But there are a lot of alien incidents in National city that she deals with as well."

"Like hostile aliens?"

"Exactly."

"So she's kind of like you then. You know saving people from aliens."

"Perhaps. But she'd rather punch her way out of problems. I like to solve them."

"True. What is there to see in National City?" Martha asked changing the subject as the Doctor had begun to emotionally distance himself from the conversation.

DEO

Winn Schott was typing away at his computer when an alert popped up. No, two alerts popped up.

"What is it, agent Schott?" Director J'onn J'onzz asked coming in from another room. He could be a bit intimidating, after all, he was the Martian Manhunter, the last son of Mars.

"We just received two notifications. One is of alien space crafts hovering just above Earth. And the other is of multiple unknown readings coming from this section of the city," Winn said pointing to the screen.

"Supergirl," The Director called into the comms.

"What's up J'onn?" She said as she slowed down her speed to hear J'onn better.

"There are some strange readings coming from your part of the city. Could you check them out?"

"On it."

"Winn, I want you to do some more in-depth scans of what's in the sky. I want to know what we're dealing with before it comes."

Above National City

Supergirl had pulled a U-turn, she had already flown over that part of the city and didn't see anything out of the ordinary but she wanted to double-check. She was flying pretty fast now, the wind blowing through her hair was the best feeling in the universe. She slowed down now so she could have a close look at what was below her. Good thing she decided to double-check, a cable had snapped and sent a steel beam caravaning towards the ground. She dove after it, then passed it. As she was about to catch it she heard a voice that had a strange accent.

"Martha look out!" He shouted as he noticed the steel beam falling towards them. The woman beside him, Martha, looked up as the man moved in front of her protecting Martha from the steel beam.

Supergirl caught the beam with ease and flew it back up to the crane and set it down where it was meant to.

"Thank you!" Martha shouted and the man raised his hand in thanks. She could only hear Martha because of her super hearing but they both genuinely looked happy that she had saved them.

Maybe I should write an article about what tourists think of Supergirl. That was Kara thinking, Supergirls alter-ego a reporter for CatCo magazine. She could go interview Martha and whoever that man was with her.

She snapped out of her reporter thoughts quickly and looked around for anything unusual coming up empty-handed.

"Hey, J'onn," Supergirl said heading back towards the DEO

"Go ahead Supergirl."

"I didn't see anything suspicious. I'm heading back to the DEO."

"Okay, Supergirl."

DEO

Supergirl landed on the balcony and sauntered into the DEO.

"Hey Kara," Alex said walking up to her sister, "How'd it go?"

"Nothing out of the ordinary. But I saved these two British tourists and I'm going to interview them and write a piece on what tourists think of Supergirl."

"That sounds like a good idea. But you never know what they're going to say."

"Don't worry, I can handle myself."

"Supergirl, agent Danvers," J'onn said calling them over, "Do either of you recognize these energy signatures?"

Kara shook her head.

"No," Alex said, "But whatever it is it must be pretty big to be giving off that much energy."

"But I didn't see anything that big when I was flying over the city."

"Then it must be in a building," J'onn concluded, "Winn any luck on identifying the space crafts?"

"No, they're not in our database," Winn said spinning around in his chair, "Neither is that strange energy coming from somewhere downtown."

"Well, you guys have fun figuring this out. I have an idea for an article," Supergirl said walking out of the room, "Call me if you need anything."