A/N: So, take Pretty Little Liars, a show about secrets, drama and teen angst. It's actually a pretty good show. Now, take a one Sheldon Cooper, a man who doesn't quite understand human nature, can't keep a secret, and acts superior to everyone around him because he's a genius. Now put him into this world of teen drama and angst.

I've had this idea in mind of a while, but wasn't quite sure if I could get it to make sense. In spite of season 2 just ending, the plot will be a mix of storylines from the second half of season one. Also, Ezra knows that Aria has told her friends about them. In this story, the girls help keep Aria and Ezra's secret and Ezra acts like a big brother looking out for the girls. Please leave me some feedback. I really want to know if the story makes sense and if there's anything you want to see happen.

Aria Montgomery was driving home from school. It was a warm, spring afternoon and there wasn't a cloud in the sky. As she was driving, she was also talking to her dad over the phone.

"Mom left this morning for Lancaster. She's going to be at Grandma's for a whole week."

"Did she say anything before she left?" Byron asked.

"Why?"

"No instructions, no contact information, no to-do list? I'm just being a concerned father."

Aria chuckled. "And I appreciate it. And even though he doesn't try to show it, Mike appreciates it too."

"Well, if you guys need anything at all, you be sure and call me."

"We will. And good luck on your lecture." Aria pulled into her driveway. "I've gotta go. Love you, Dad. Bye."

As Aria walked up the front steps of her house, she stopped and looked up at the sky. She felt the spring sun on her face. She could hear some birds chirping in a nearby tree. She could hear Mrs. Barnes across the street, playing the Beach Boys on her radio. She took a few deep breaths and sat down on her porch.

Aria Montgomery's life was far from perfect. She had to deal with a lot more than the typical teenage girl. While most girls were worrying about acne, finding the right outfit and not embarrassing themselves in front of the school hunk, Aria had to deal with a messy divorce between her parents, a younger brother with a ton of anger issues, a scandalous romance with her English teacher, Ezra Fitz, and a mysterious stalker known only as A who knew all of her dirty secrets. And just a few weeks ago, A had supposedly tried to kill one of her best friends, Hanna Marin, with a car, because she allegedly 'knew too much.' (By the way, Hanna was recovering well and was coming home tomorrow. Hanna's friend, Mona, had been planning a Welcome Home party for her for over a week.)

Yeah, Aria didn't have normal issues, and sometimes it was more than she wanted to handle. But for the next ten minutes, Aria Montgomery had a perfect life. She lived in a small, quiet, little town, she had three great friends, two loving parents and her boyfriend/teacher was taking her to see a movie tonight. And, oh, her parents were both out of town for a week. Her mom was visiting Grandma in Lancaster, and Dad was participating in a literature lecture in Philadelphia. So for the next week, Aria was in charge of the house, which didn't sit well with her brother, Mike. She chuckled.

Aria sat there for a good ten minutes. When it was over, she took one last deep breath and headed inside, back to her normal life.

As Aria came into the house, she found her brother, Mike, planted on the couch in front of the TV.

"What are you watching?" she asked, as she made her way to the kitchen. She grabbed a soda from the fridge, and then, came back into the living room.

"NCIS," Mike answered, "It's Spencer's favorite episode."

Aria almost did a spit take. "You mean the Twisted Sister episode?"

Although NCIS was a popular program across the country, it was perhaps most popular in the town of Rosewood, because of Aria's friend, Spencer Hastings' uncanny resemblance to Troian Bellisario, the actress who played Agent McGee's younger sister. After the episode had first premiered, many people who had never met Spencer had begun following her around, believing that she was Ms. Bellisario. Spencer had enjoyed the attention, but after a day or two, it had started to get old. Eventually, the principal made an announcement that Troian Bellisario didn't go to school at Rosewood High and to stop pestering Spencer. Still every once in a while when some kid who didn't know her asked if she was Troian Bellisario, she would say 'yes', just for laughs.

Aria watched with Mike for a few minutes.

"So, do you have any plans for tonight?" She finally asked.

"Hockey practice, right after this." Mike answered. "You?"

"I'm going over to Spencer's for a study date. I'll probably be back around ten."

Mike nodded. "Oh, and FYI, Mom may have left you in charge, but don't expect me to like it."

Aria smiled. "Noted."

BOOM!

Aria and Mike were spooked by a sudden explosion that rang through the house.

"What was that?" Aria asked.

"Why do you automatically assume that I would know?" Mike snapped back. The two siblings sat there in hushed silence for a moment, before determining the source of the noise. Once they had, both of them bolted upstairs towards the attic.

When they opened the attic door, they were greeted by a large, smoking, wooden box. It looked like a wardrobe. Aria picked up a fire extinguisher by the door, just in case the smoke was from a fire.

"What is this thing?" Aria asked, rhetorically. She and Mike paced around the box, not sure what they should do about it.

"How did it get in here?" Mike asked. "Wasn't through the door, we would've seen it. And the window's too small and too high up."

Just then, they heard a knock from inside the box.

"Oh my gosh," Aria exclaimed, "There's something alive in there."

"Could be aliens," Mike joked. Aria rolled her eyes.

The box knocked again. "Open it, Mike."

Mike glared.

"Please?"

Mike carefully inched toward the door and pulled it open. A man fell out, a tall, thin, scrawny man with short dark hair and a red t-shirt with an exploding computer on the front.

"I was right," said Mike, "Aliens."

Aria set down the fire extinguisher and stepped over to the unconscious man and gently nudged him with her shoe. "Uh, sir?"

The scrawny man awoke with a sudden start. Everyone jumped and screamed.

"Great Caesar's Ghost!" shouted the man, "Where am I?"

"Umm, Rosewood," Aria replied, "Rosewood, PA. In the Montgomery household. I'm Aria, and this is my brother, Mike. And who are you, sir?" The scrawny man ignored her for a moment and stepped back into the wooden box. Aria and Mike peered in and gaped in amazement. Inside, the wooden box was decked out with all sorts of hi-tech equipment and computers. It looked like something out of Star Trek.

"It worked," said the man. "It actually worked." He was starting to speak in an arrogant tone. "I have taken a giant leap for both man and mankind. Nobel Prize, here I come!"

"Excuse me!" Aria shouted, getting his attention. "Who are you?"

"Oh, where are my manners? Dr. Sheldon Cooper, PhD, Caltech, Earth Prime. Pleased to meet you. And you are?"

Aria stared at him. "I just said, I'm Aria Montgomery and my brother, Mike Montgomery."

"Oh, well, I may not have heard you the first time. That always seems to happen when I get caught up in my work."

"So what is this thing?" Mike stated.

"This…is my special project. I call it…a TARDIS."

"A 'what' now?"

"A TARDIS. It's short for Time And Relative Dimension In Space. It's the ship from Doctor Who."

"Doctor what?" Mike replied. Sheldon grumbled. "Look, in layman's terms, this ship of mine is designed to travel in time, space and across dimensions. I'm from the central dimension that I have dubbed 'Earth Prime'. According to these readings, I have move in left ascension across three dimensions before arriving here. So I guess that makes this Earth-4."

Aria didn't understand half of what Sheldon was saying, but she tried to be polite anyway.

"Well, welcome to our dimension, Dr. Cooper." She reached out her hand to shake Sheldon's, but he backed away. "I won't hurt you."

"Oh, no," Sheldon replied, "it's just that I'm a germaphobe. I wash my own hands as often as I can, and don't think it's wise to acclimate myself with any foreign contaminants. But Mahalo to you."

Aria lowered her hand.

"So what is this thing exactly?" asked Mike.

"Like I said earlier, it's a TARDIS. It's based on the ship used by the title character on the series, Doctor Who."

Mike just stared at Sheldon and chuckled slightly. "You built this based on a TV show?"

"Yes." Sheldon replied. "In actuality, the TARDIS is supposed to be bigger on the inside and can shapeshift as it travels from one location to the next, but let's be realistic. Oh, by the way…" Sheldon ducked back into the TARDIS and pulled out a DVD and handed it to Aria. Aria read the cover out loud, "The ABC Guide to Earth-Prime: Everything You Need to Know About the Central Dimension. Narrated by Dr. Sheldon Cooper."

"It's based on Carl Sagan's Golden Records," Sheldon said, proudly. Aria stared with a look of bewilderment. "I don't know what that is."

Sheldon rolled his eyes thinking, 'I'm I the only smart person here?'

"When they sent up the Voyager probes, renowned astronomer/astrophysicist Carl Sagan sent up a record made of gold with each probe. The records contained information about the planet Earth for any extraterrestrial civilization that may find them. This DVD is my spin on that. It contains information about my Earth for the reference of those living in other places and times."

"Oookay," Aria replied, still somewhat bewildered.

"So," she continued, "Now that you're here, what do you plan to do?"

"Well, with your permission, I would like to explore your town for my assessment. Y'know, see what difference there are between our two cultures."

Aria glanced at Mike. "Can I talk to you outside?" he asked.

Aria followed Mike out of the attic and closed the door behind them.

"Tell me you're not buying into all this," Mike exclaimed.

"Of course not," Aria replied, "I'm actually hoping this is all just a weird dream. But for the time being, he seems harmless. A little crazy, but harmless."

"So let's say we let him outside, he starts reeking havoc on the town and it gets traced back to us. Then what?"

"Mike, he's not an alien invader."

"As far as you know."

Aria sighed. "As soon as he's done, we'll see him off, alright?"

"Alright, but how long does he plan on staying?"

Aria paused. "Let's go find out."

"Okay, Dr. Cooper, we've reached a decision, but first, I have to ask, you don't plan on staying long, do you?"

"Oh no, just an hour or two to make some observations, then I'll be on my way."

"Very well, then you may make your observations, but as a favor to my brother and I, please don't draw attention to yourself. We have the house to ourselves this week, and the last thing we need is to be swamped by the press and the military for harboring an alien."

Sheldon nodded in agreement. "I understand and accept your terms. But first, I could use some cereal. Do you have anything low fiber?"