Sherlock and John were in the middle of an irrelevant conversation as they left the crime scene. Sherlock waved his arm out for a taxi as he concluded. "That's why the eyeballs were in there," he explained with a slightly guilty look on his face. This wasn't the first time John had seen this look.

"Look Sherlock, I don't care why they were in there, I just want you to consider my comfort zone when using the microwave," Sherlock rolled his eyes at John. It's not like he would understand. Nobody understands him, except maybe Moriarty, and he would love to discuss things with him if Moriarty weren't trying to kill him.

The black vehicle pulled up on the side of the road. John went towards the door but stopped.

"Problem?" queried Sherlock.

"There's already someone inside," replied John. Sherlock opened the door to find a person (he couldn't tell the gender in the shadow of the interior) sitting opposite Sherlock and John's usual seat.

"I don't mind if you join me, Sherlock Holmes, we're going to the same destination," came a voice from inside. Sherlock and John looked puzzled, Sherlock recovering first and whispering into John's ear as he entered the cab.

"Could be dangerous," John straightened and sat in the taxi next to Sherlock.

Sherlock could tell by the voice that the passenger was a woman. She had short black hair, like Sherlock's, except straight. John wondered if Sherlock's hair would look like that if he straightened it. The woman was clearly younger than the two of them and wore a purple tailed coat with skinny jeans and black canvas shoes. Next to her were a top hat and a cane with a large blue glass ball on the top. Her eyes were blue, but much more electric and piercing than Sherlock's. There was silence in the cab for ten minutes until Sherlock started with his questions.

"Alright, who are you and how do you know me?" his fingers steepled and his eyebrow raised in question.

"You tell me, Sherlock," she grinned and tilted her head slightly, shifting a glance to John as he sat quietly in confusion.

"You're Australian, I can tell from your accent…" the woman straightened her head and turned to Sherlock.
"But?"
"But, you have a hint of an English accent, meaning you've lived here long enough to acquire one. You come from a rich family, given the state of your clothes and your hair. Far too shiny for a common woman. You are introvert, thus very pale skinned but you have an even paler band across your left ring finger, showing that you've been married even though you're only…let's say… late twenties," the woman's face hadn't moved since he started, giving no hint of correction to Sherlock, which made him slightly annoyed, "your right hand is on top of your left as it's resting on your knee and your right leg is crossed over your left, so you're right-handed. You don't have a limp, your cane is too decorative for practical use."
"So what am I?"
"Intelligent. But not as intelligent as I am."
"You think so?"
"Positive," Sherlock said with a smile, "how did I do?"
"Poorly," Sherlock's smile disappeared as her words slapped him in the face. Poorly? Surely I am correct, when have I ever been wrong? He thought.

"Oh really? Do share." The woman grinned again.
"Well, you did get a couple of things right, but I'll tell you the whole story. I am Australian but today is the first day I've been in England, my father was Irish but moved to England when he was young, thus obtaining an accent which he passed to me when he moved to Australia. My family is extremely poor but I've managed to get enough money on my own to afford this outfit. I am introvert, as people call me a freak, much like they do to you, dear Sherlock," John winced at the word 'freak'. He hated it when people called Sherlock a freak, "but the band on my finger was from a ring my mother gave me when I was young, too small for the middle, too large for the pinky. I'm twenty-one, and I'm not right handed, I'm left-handed, even slightly ambidextrous."
"Amazing," Sherlock and the woman whipped their heads towards John, who sat there wide-eyed at the brilliance that filled the taxi. Sherlock scowled at the woman and she smiled warmly.

"I know everything about you, Sherlock. More than even you know. Even things you don't know about your friend…"she shot a sly grin towards John, who cowered slightly under her gaze.

"So where are you going?" John wondered, trying to steer the topic away from everyone's background story.

"You really are stupid, aren't you? It must be so terribly dull in your quaint little mind," Sherlock growled slightly, but only John seemed to hear, "I told you before you got in the cab that we were going to the same place."
"Baker Street? What on earth would you be doing there?" He questioned again.

"Same thing you're doing, going home. 221 Baker Street."

"That's where we and Mrs Hudson live," snapped Sherlock, "I doubt there's any room in either flat for you to stay, and even if there was you're not living in our flat."
"I'm afraid you misunderstand. I'm not living in 221a or 221b, I'm moving into 221c. Mrs Hudson fixed the room especially for me."
"Why would she do that?" Sherlock was furious, not only had this woman made a fool out of him, but she was moving into the room underneath him? There has to be an explanation.

"You and Mrs Hudson are going to have to put up with me. You both were in on my father's death," as her sentence finished, the taxi pulled up outside 221 Baker Street. The woman got out first and moved her head inside of the taxi door, "The name's Xiakara and the address is 221c Baker Street" she winked and made a small clicking noise, imitating Sherlock when he had first met John.

John paced around the room, the events of the morning still flashing through his mind.

"Who was she? Why here, why now?" he gave up thinking and slumped into his chair, looking out the window for something remotely interesting before turning to Sherlock, lying on the sofa with his blue silk robe and his hands steepled under his resting face. He was deep in thought, clearly it was a nicotine patch problem, as he could see a couple where his sleeve had fallen past his elbow. "Three patches? This is a three patch problem?"
"No, John, there are six, this is a six patch problem." Sherlock replied, his eyes still closed in thought.

"Six patches? Six nicotine patches? Sherlock, you'll kill yourself!"
"I am aware," John opened his mouth to speak, then closed it and shook his head. Sherlock opened his eyes and turned his head towards John, "problem?"
"Yes, Sherlock, yes there is a problem. You get outsmarted by some stranger in a cab and now you're trying to kill yourself with nicotine!"
"I wasn't outsmarted I was fooled. She is clever, I'll give her that. I can tell things about people because they are obvious habits. Normal people have obvious habits."
"So she's not normal then?"
"No…no, she's like me, and the cabbie from our first case…and Moriarty…"
"A genius?"
"Yes… How interesting… I have another genius living right underneath me."
"It is interesting, isn't it?" Xiakara cooed. Sherlock sat up as a square of the floor shifted next to the sofa.

"What the…?" John started. Sherlock blushed as he realized she'd found his homemade garbage chute for when he was too busy to take it to the bin. 221c was probably littered in his old experiments. Mrs Hudson would probably make him pay extra for that.

"Sorry to intrude boys," she glanced at Sherlock, who seemed to get more flustered by the emphasis she put on that last word, "I thought I'd make a suggestion for an experiment of yours," she produced a tub of margarine with the remnants of four fingers and a thumb inside. She pushed it to Sherlock's slippered foot, "Try sodium and sulfur," she winked at him as she pulled the floor back over the gap.

"What was that, Sherlock?" John had his hands on his hips as Sherlock looked at him in embarrassment, a look rarely seen by the doctor.
"A…Garbage chute…"
"A garbage chute?"
"Yes."
"A chute for garbage that leads to 221c, the room right underneath us?"
"Yes."
"Why is it there?"
"I'm busy on garbage day."
"You're-!" John started before throwing his hands up and heading to the door.

"Where are you going?"
"Out, I need some air."
"Don't leave me with-" the door slammed shut behind John and Sherlock could hear him storm down the stairs, "…her" he finished with a tone of resentment in his voice. He curled up onto the sofa and closed his eyes, trying to figure out his problem before John got home and became distracting.