Author's Note: I needed a break from Moriarty fics and I've been wanting to do a sis-fic for a while. Even though I'm using Nancy Springer's Enola Holmes, she is technically an OC as she is entirely my own interpretation. Hope you like. Please review =)

"Two murders, two victims seemingly unrelated killed in their own home, no sign of forced entry," Sherlock stated loudly as he paced his living room. "What relates the murders? I'm glad you asked, John. Despite being murdered in their own home, both victims bore the exact same stab wound entering just below the heart, the dimensions of the incision depicting identical murder weapons. The question is, how are these two people related and why were they killed?"

Watson frowned. This was the fifth time Sherlock asked that question. It had been a while since he had seen the great detective so stumped and his frustration was evidently escalating. Watson had taken time away from Mary to help him with this case but as there was not a whole lot to go on he felt a bit useless.

"Why don't we take a break? Clear our minds a bit." Watson suggested, shutting the laptop he had been taking notes on. Sherlock flipped the laptop open again with a steely glare.

"I can't clear my mind, John, I need it," he spoke.

"You know what I mean," Watson sighed.

"Yes, and 'clearing my mind' means undoing all my deductive paths of reasoning."

Sherlock screwed his eyes shut with his fingers to his temples and began muttering random things repeatedly under his breath.

Watson sighed again, cupping his chin in one hand. Poor Sherlock. He hadn't been quite the same since he came back from the dead. Maybe he was making an effort to distract himself from his current situation. Maybe he was trying in his own bizarre way to deal with Watson getting married and moving on.

"Would you stop that?" he said, growing unnerved by Sherlock's behaviour, "You're going to burst a vessel or something."

A knock on the door drew both their attention.

"Hope I'm not interrupting," came Mycroft Holmes' voice as he let himself in.

"Undone," Sherlock grumbled resignedly, dropping his arms melodramatically.

He spun on his heels to face Mycroft.

"What do you want?" he snapped.

"Hello, Mycroft," Watson said cheerily, lifting his tea cup by way of greeting. It was best to be polite to one of the most powerful men in Britain. Mycroft responded with a nod before addressing his brother.

"I'm leaving the country for a while," he said.

"Oh good. Bring us back a t-shirt this time."

A sharply dressed man with impeccable posture stepped through the door carrying two large suitcases.

"And I heard there was a room available here."

Sherlock looked at the suitcase man.

"Not him," Mycroft chuckled, "Our sister."

Watson choked on his tea.

"Did I hear that right?" he spluttered, utterly taken aback, "You have a sister? Seriously? Any other secret siblings you want to tell me about?"

"Has it been ten years already?" Sherlock seemed to wonder, and Watson wasn't sure whether he really didn't know or he was just using a figure of speech.

"They grow up so fast," Mycroft responded.

Watson was well aware of the Holmes brothers' petty rivalry with each other but underneath all of it there was no denying the brotherly love and respect for one another - even if neither would outright admit it. But the way they spoke of their sister just now… there was a distinct absence of familial acknowledgment, as if having a sister was nothing more than a fact to them.

"Wait," Sherlock said, eyeing his brother with suspicion, "Why here?"

"Like I said," Mycroft replied, "I'm out of the country and you have a spare room. Besides, living in the heart of London would do her good, give her a chance to find a job and her own place."

"No."

"No?"

"I'm not accepting flat mates at the moment."

"I'm not asking." Mycroft stated, the tone of his voice switching from amiable to firm, "Besides, its only temporary."

"My ears are burning!"

A girl in her early twenties appeared from behind Mycroft. She was tall and skinny with long arms and legs. Her light brown hair was gathered in a long poofy ponytail and she had small blue eyes and aquiline features. Her thin pink lips were taut in a shy smile. Watson noted her physical resemblance to her brothers, but physically was where resemblance seemed to stop. Where the boys carried themselves with pride, charisma and egotism, Enola's body language was that of a normal, shy young woman, coming to terms with having to face new responsibilities with her coming of age.

"John, meet Enola the youngest," Mycroft said.

The girl waved nervously.

"Nice to meet you, Enola," Watson said, "I've heard almost nothing about you." He shot a look to Sherlock who mouthed a "what?" as if he had done nothing wrong.

"I'm not surprised," Enola shrugged as if it weren't a big deal, "I've been away at boarding school for so long. I'd like to unpack if you don't mind." She thumbed at the pack she was carrying on her back.

Mycroft pointed down the hall towards Watson's old room and with a quick thanks she collected her bags and followed his directions.

"This is not a bed and breakfast," Sherlock said to Mycroft as soon as the bedroom door shut behind Enola.

"I just need someone to keep an eye on her while she adjusts to the real world," Mycroft reasoned, "Lord knows it could have done you some good back in the day."

"I highly doubt that."

Mycroft opened his mouth to argue but then shut again as he appeared to agree.

"Perhaps you're right," he said, "Anyway, I best be off. Got a plane to catch. Sherlock, John, it's been a pleasure as always."

"As always," Sherlock muttered through gritted teeth.

Mycroft proceeded to follow the suitcase man out of the flat when he stopped and turned his head back slightly. "Oh and one more thing," he said, "try not to place our baby sister in any undue peril. Mother doesn't need the grief." And with that he left.

There was a moment of repose in which Watson expected Sherlock to explain the situation. Sherlock being Sherlock however just tightened his dressing gown around him and appeared as he always does when he's trying to solve a case. Irritated, Watson decided to interrupt his train of thought.

"You never told me you had a sister," he said.

"So?" Sherlock retorted, not changing his stance.

"So why didn't you?"

"I forgot."

Watson sat back, shaking his head with incredulity. This was just so typical.

"Forgot to tell me or forgot you had a sister?"

Sherlock snapped out of his trance, clearly irritated by Watson's interrogation.

"She's been in boarding school! I hadn't seen her since she was eleven!" Sherlock cried, throwing his arms up in exasperation, "With more pressing things like multiple murders to think about, an estranged sibling would hardly be at the forefront of my mind."

"Well at least properly introduce me for heaven's sake!" Watson cried, standing now.

"Fine!"

Sherlock stomped down the hallway and rapped on Enola's door.

"Enola?" he called, giving Watson a disapproving glare, "Would you care to join us?"

There was a moment of silence before Enola emerged, zipping up her coat as she headed for the door.

"Wait, where are you going?" Sherlock demanded

"Out," came Enola's reply and suddenly Watson could see the missing resemblance all too clearly.

"Out where?"

Enola turned back to him and produced a hefty wad of notes from her pocket.

"A graduation gift from Mycroft," she said, "Since I've been wearing the same damn uniform for ten years I think it's only imperative to spruce up my wardrobe. Simply put, I'm going shopping. Don't wait up, I already have a key. Nice to meet you, John."

She gave Watson a nod of acknowledgement before she left.

"Well," Watson said as he heard the front door slam shut, "I had my doubts but I now certainly believe you two are related."

"Whatever." Sherlock seemed to dismiss the idea that he had just been reunited with his sister after ten years.

There came the bleep of an incoming text message and Sherlock pulled his phone from his dressing gown pocket.

"Ah-ha!" The detective's face lit up with glee. "Get your coat, Watson. There's been a third murder. We officially have a serial killer on our hands." Sherlock grabbed his coat from the back of the chair and headed for the door.

"Sherlock," Watson sighed, "Clothes."

Sherlock looked down at his dressing gown.

"Quite right," he said showing no embarrassment as any normal person would, "I'll just be a moment." He then disappeared into his bedroom.

Watson sat back down with an elbow on one knee and resting his chin in his hand. He couldn't have normal. Nope. A third murder. A third Holmes sibling. Just another day-in-the-life of Dr. Watson. Well, at least he had something interesting to tell his fiancé when she asks him how his day went.