Author's note: This story is rated M for some foul language and some sexual scenes later in the story. Enjoy!

Sherlock needed a new flatmate.

It had barely been two months since John had moved in with Mary and already Sherlock had managed to completely destroy the apartment. Books were stacked in haphazard and teetering piles in practically every corner of the the room. Papers were strewn across tables and the floor, a forest of them tacked to the wall above the fireplace. Scorch marks poked their heads out from under books and papers, one clinging to the ceiling and making itself known by the heavy charred smell. John didn't dare look in the kitchen.

Then there was also the fact that Sherlock now had to pay for the entire flat instead of half and he was falling far behind. Mrs. Hudson was kind enough to allow him time to catch up or find a new flatmate to share the expense. So far, none had been found and Sherlock, the stubborn and prideful bastard, refused to ask anyone for help. And asking for help from Mycroft? Out of the question.

As he stood in the doorway of the absolutely disastrous flat, John knew he had to find someone and fast. But finding someone who would be able to deal with Sherlocks rather...frustrating personality, was proving to be a difficult task. So far, every potential flatmate that John had brought in, Sherlock had eithar scared off, offended or turned down before they even stepped through the door.

"Sherlock," John called out.

The consulting detective's head popped out of the kitchen, followed by the rest of him, a rag in his hands stained with various unknown substances. "Ah! John! Hello-" Sherlock stopped short, "Did you bring another one?"

"No, Sherlock, I didn't," John said, "Do you know why?"

"I always know-"

"Shut up, Sherlock," John said, a slight hint of irritation in his voice.

"John?"

"Almost the entire London population has passed through that door, willing to try and take you on as a flatmate," John said, "And every single one has run away terrified or been sent away by you."

"And the problem…?"

"The problem is, Sherlock, there is no one left. I can think of no one else who is in desperate enough need for a place to deal with you."

Sherlock tilted his head.

"Did you ask Lestrade?"

John threw his hands up in the air, "I've asked everyone! Lestrade, Molly, Mary, Anderson, Donnovan, I even asked Mycroft!"

Sherlock's expression darkened at the mention of his brother's name and took on a look of annoyance. John noticed shift in expression and jabbed a finger in Sherlock's direction, "Don't you dare pout on me, Sherlock, Mycroft was last resort."

With a snort, Sherlock headed back into the kitchen, John following close behind. The kitchen was a worse mess than the living room, and there was a faint trace of some indistinguishable smell. "I'm serious, Sherlock, there is no one left," John continued.

"Then why don't you move back in with me?" Sherlock said, picking up a vial and observing it's contents.

John sighed and replied, "You know very well I can't. I'm married now and I have a child on the way, it wouldn't be fair to Mary or the baby."

Sherlock was silent.

Shaking his head, John left the flat and started down the stairs. As he reached the front door his phone rang his pocket. John picked it up and answered glumly, "Hullo?" His eyes lit up when he recognized the voice at the other end.

"Sorry, just dealing with something right now," John replied to the person on the other end.

John walked out the door and towards the cab where Mary stood waiting for him. The person on the end spoke and John's face broke into a grin. Mary tilted her head in question and John held up a finger telling her to hold on a moment.

"You're moving to London?" John asked.

The caller replied.

"Oh, I'm so sorry to hear that-"

The caller spoke again.

"A place to live…? Well…" John looked up 221B Baker Street and grinned, "I have the perfect place for you."

John and the caller exchanged a few words and then goodbyes and John hung up. He turned to Mary with a wide grin on his face.

"Who was that?" Mary questioned.

"Let's just say that I think i've found the perfect flatmate for Sherlock, "John said confidently.

Mary raised an eyebrow and replied, "and who would that be?"

John chuckled.

"Charlie."

John stood in the London International Airport, crowds of people passing to and fro. Some rushed past in order to catch their flight on time, others strolled by lazily, most likely on vacation. John just stood there waiting.

After John decided that Charlie would be a perfect replacement as Sherlock's flatmate, he called her back. John explained the situation. Charlie would be sharing the flat with the man that John had been previous flatmate's with and would be paying half rent. She accepted almost immediately. Before John hung up, he explained that the man she was going into a flatshare with was a little difficult to live with to which Charlie replied, "John, I've fought in the war, how bad can he be compared to that?"

John chuckled and told Charlie that he would meet her at the airport, which is how he managed to find himself standing across from one of the gates, being bumped and stared at by passerby's, waiting for Charlie's flight to arrive. He didn't have to wait very long, he soon saw the plane pull up and attach to the gate. Soon, streams of people came pouring out. Men, women, and children and occasionally a carrier with a small dog inside.

Suddenly, John saw a shock of long white blond hair barely peeking out from behind a tall man. The man stepped to the side and John saw Charlie. She was a small thin woman with a strong yet still fair face. Heavy blond eyebrows hung over to dark brown eyes darted back and forth, trying to locate John. Her small hand clasped the handles of a large army duffel bag that was almost bigger than her body.

"Charlie!" John called out, waving his hand.

Charlie's head turned as she heard her name being called. Her eyes fell on John and her face broke out into a grin. "John!" she said happily. She trotted over to John and dropped her bag at their feet, throwing her arms around her long time friend.

"Holy cow, how're you doing, John?" Charlie said, leaning back and taking in John's face. John noticed that most of Charlie's american accent had returned since he had last seen her in Afghanistan.

"Good, married and have a baby on the way," John replied with a proud grin.

"Shut up, seriously?" Charlie said, her smile growing causing her dimples to deepen and the corners of her eyes crinkle, "Congratulations!"

Charlie released John and picked up her back. The two talked as they walked through the airport to the luggage pick up where they waited for Charlie's bags to come around on the belt. When the two bags were retrieved they walked out of the airport and out on to the sidewalk were John hailed a cab. They loaded Charlie's things into the small trunk and climbed in.

"So," Charlie began, "Tell me about Sherlock."

"All I can say is that you will never be bored," John stated.

Charlie raised an eyebrow. "He can't be that bad," Charlie said looking at John.

Shrugging, John pulled out his cellphone and said, "Don't say I didn't warn you."

John texted Sherlock, knowing that the consulting detective was more likely to respond through text than bother to answer a phone call.

Sherlock. -JW

What is is, John? I'm busy. -SH

John rolled his eyes.

I found you a new flatmate. -JW

Really? That's good news. -SH

Name is Charlie. Was an old buddy of mine from when I was in the war. -JW

Lovely. -SH

We're on our way to 221B right now. -JW

John immediately sent another message following the first.

Behave and be nice, alright? -JW

There was a silence from Sherlock and John wondered if maybe the message hadn't sent...or Sherlock was just being his usual irritating self and had lost interest and had moved on to the next thing. John's phone beeped.

No promises. -SH

John rolled his eyes and shoved his phone into his pocket.

Sherlock sat on the couch, his fingers steepled under his chin as his eyes flitted across the case file Lestrade had given him when John came thumping up the stairs.

"Good evening, John," Sherlock said without looking up from what he was reading.

"Charlie will be right up," John said, "And I'm serious Sherlock, behave, this is your last chance. If this doesn't work I can't help you anymore, you'll have to go to Mycroft."

Sherlock's head snapped up at his brothers name and his face filled with irritation. He closed the file and stood, waiting for his new flatmate to come tromping up the stairs.

"John? Which door?" A voice called.

Sherlock's eyebrows furrowed together in confusion. The voice, whom Sherlock assumed belonged to Charlie, sounded quite american and...female?

"Right up the stairs," John called out the door, "It's the one with the door wide open."

The footsteps grew louder and to Sherlock's surprise, though he would never admit he was caught off guard, he found himself staring at a small woman with a mop of shocking blond hair that ended just past her hips. Deep brown eyes wearing a baggy shirt and close fitting jeans.

"You're a woman," Sherlock stated.

"And you're observant," Charlie replied sarcastically.

Sherlock blinked and looked at John then back at Charlie. He saw no scars, no dark look that his behind the eyes. She didn't carry herself like a soldier, like John did. If John hadn't told him that he and Charlie had been in the army together, he never would have thought that she had even fought. This threw Sherlock off, he had always been able to trust his eyes and deductions, but now…

"I think you're friend is broken…" Charlie said to John.

"Sherlock?" John said.

Sherlock blinked and shook his head, falling back into his typical composure. He turned and strode over to the leather chair and sat down, draping one long leg over the other. "Come, sit Miss…"

"Abernale," Charlie offered.

"Miss Abernale," Sherlock said with a nod, "I have a few simple questions for you."

"Sherlock…" John said in a warning tone.

Charlie dropped her bag to the floor and strode over, sitting in the armchair across from Sherlock. The consulting detective stared at Charlie, his eyes flicking up and down her body, taking in every detail that might hint at who she was.

"How do you feel about the violin?" Sherlock questioned suddenly, his fingers tented under his chin and his elbows resting on the arms of the chair.

"No bother," Charlie replied.

"At 2AM?"

"Rather soothing."

"Good," Sherlock said. He uncrossed his legs and leaned forward. "Now, I'm assuming John has told you about me?" Sherlock said.

"Yes, he told me that you are utterly brilliant and have the unique ability of being able to deduce a person's life story from their watch and the socks they wore that day…"

John could practically see Sherlock's ego inflate in front of his eyes.

"...he also told me that you can be quite the irritating bastard who is unbelievably lazy and even though you have the brain of a supercomputer you have the mentality and patience of a two-year-old," Charlie said with a pleasant grin and a twinkle in her eye. John couldn't help but chuckle quietly as he saw the confident smirk slowly slide away and fall off his face. Sherlock looked at John with an irritated pout.

"What?" John said, biting back a giggle, "I had to tell her what she was getting herself into."

"I see," Sherlock said, turning his back to Charlie who sat across from him with a faint smile on her face. Sherlock wanted nothing more than to wipe the smile off her face. The corners of Sherlock's mouth quirked up into a smile.

"You seem to be a very interesting potential flatmate, Miss Abernale," Sherlock began, rising from the chair and circling around Charlie, looking quite predatory. Charlie remained still, her arms across her chest and her eyes following the consulting detectives movement. "However," Sherlock continued, "While you have heard of me, I know nothing of you…"

"Fire away," she said.

John stood back by the doorway, watching with amused eyes. He knew that considering Charlie as a flatmate for Sherlock would potentially lead to drastic consequences, but she was the only one that John could think of who could handle Sherlock. Charlie was hard headed and patient and as Sherlock would soon find out, smarter than she appeared.

"You're american, as heavily indicated by your heavy accent, but an idiot with ears could observe that. The plane ride over was quite noisy and long with many loud children and annoying residents. You weren't bothered by it however, for you grew up in a large family, thus suggesting you were more easily able to ignore the annoyances around you by putting in earbuds and blocking out the noise with some loud sound, probably music, as the earbuds are hanging out of your pocket with small traces of ear wax residue on them. I suggest cleaning out your ears. You tried to get some sleep on the plane but considering that bags under your eyes, you received none. From what I've observed from John, it was most likely due to nightmares of the war. Which brings me to another thing, you have PTSD; however, you have quite a handle on it. I must admit, if John had not informed me that you had been in the war with him, I would not have guessed," Sherlock said in the fast paced tone he acquired when voicing his deductions, "From the lack of scars you more than likely worked at a medical base, taking in emergency patients and healing them, that's where you met and became acquainted with John."

Sherlock stood there triumphantly, expecting at any second to be bombarded with an amazed, 'wow, how did you do that?'

Charlie merely smirked.

"Wrong," Charlie said in a singsong voice.

Sherlock's face fell.

Removing the earbuds from her pocket, Charlie stepped towards Sherlock. "I am american, you got that part right, obviously. The plane ride was actually quite pleasant...I found the earbuds on the floor of the bathroom," Charlie said, draping the earbuds over Sherlock's shoulder, "I knew from what John told me that you notice the tiny things so I figured I'd try to throw you off the scent. You were also wrong when you said I had a large family. I grew up with a brother who died when I was two and parents who taught me that women were only meant to bear children and say nothing else. So I grew up learning to be quiet and patient. You weren't far off from the PSTD, I still flinch at loud noises and have the occasional nightmare, however…"

Charlie stepped forward so that there was barely a foot of space.

"I wasn't positioned at some medical base," Charlie continued " I was a special ops officer, I met John when I miscalculated and hit a landmine, he came in with his team and saved my life."

"But you have no scars…" Sherlock snapped, trying to regain some of the control he had lost.

"Oh, they're there," Charlie replied.

"Show me," Sherlock commanded, eyes darting across Charlie's t-shirt as if the scars would miraculously show themselves through the material.

Charlie snorted. "Not a chance," she said, stepping back and picking up her duffle bag. She turned to John, "Which room will be mine?"

"First on the left," John replied, trying to hide his grin.

"Lovely," Charlie said. She headed towards the room, calling over her shoulder, "We'll discuss more about the shared payment when I finish unpacking."

Sherlock looked at John with the most unsure expression that he had ever seen on the man before. John walked up to the man and patted him on the back, saying, "Good luck."

He then left, leaving Sherlock standing in the living room.