"Hello, Sherlock."

From his place at the windowsill, the man addressed slowly lowered his violin from his shoulder. He had stopped playing, of course, when he heard the woman's light footsteps- alerted not by a heavy tread nor hefty weight but by the slight tap-tap-tapping of her heeled boots against the wooden stairs.

Turning, he found himself face to face with familiar eyes. They were black and beady, simultaneously sunken and bulging- perhaps with the pressure of genius or madness pushing within the man's skull, or perhaps it was the pronounced, blackened bags beneath them that merely created an illusion.

It had always been Moriarty's eyes that got to Sherlock the most. And, he thought, Moriarty must've known it- he did, after all, make the effort to die with his eyes open.

That's right, Sherlock remembered. Moriarty's dead.

So who was this?

"How did you get in?" He stalled, hoping to reach his own conclusions about the woman before she had much of a chance to answer his many questions herself.

The woman standing before him was short, like Moriarty had been, standing at only 160cm. Her hair was the same dark brown as well, but kept at a longer length and falling around her shoulders in gentle waves. Her skin was just as pale, her lips just as pointed, and her face only slightly more rounded and feminine than her male counterpart.

"Your door was unlocked, of course."

The accent was the same too.

"Of course." He replied.

She was just as sharply dressed as Moriarty had always been, donning a long-sleeved, black lace-trimmed dress falling just above her knees with black boots and tights and gloves- formal enough to be professional but not too formal as to be noticed. She had left no skin exposed other than that of her neck and face.

"I suppose that must've been John's job." The woman entered further into the flat, her gloved hand gently running over the back of John's chair. "Things like personal security are far too tedious, far too boring."

Slowly, she tilted her head- familiar as well. "And you don't like to be bored, do you Sherlock?"

And in that moment- when that unmistakable yet undefinable and definitely inimitable light entered those unmistakable yet undefinable and definitely irreplicable eyes- he knew who she was.

She saw the recognition, as he knew she must.

"Good." She said, "That saves us time." She then crossed over to the chair closest to Sherlock, the one Moriarty had occupied all those years ago.

"Why are you here?" He questioned, placing his violin in the corner and moving over to his own chair.

"Not going to offer me tea?"

"You'd hardly accept it."

"No," She replied. "Nor do I think you could adequately make it. One of those tedious things, tea making. Though perhaps necessity has proven a sufficient motivator now that you no longer have a live in one to do it for you."

"Why," He began teeth gritted, before being cut off as she continued.

"Besides, you've only just had some, haven't you? Your landlady had two empty cups in her hand when she let me in downstairs, and I hardly think she's entertaining company at this hour. Though perhaps-"

"Why are you here?" He yelled out, losing patience.

"Now, now Sherlock, don't get frustrated." She tutted, unconcerned as she removed her left glove and began to pick absently at the lace on her sleeve. "I'm here to say hello, of course."

"No you're not." Sherlock replied.

"No?"

"No."

She sighed. "Well then, why don't you tell me- you seem to have all the answers."

"Not all of them. Just most."

Her lips quirked upwards in a lopsided smile, sitting back in her chair and gesturing for him to continue- to deduct.

"You're clearly not here for revenge." Sherlock scoffed. "If you were upset with me about your brother's suicide you would've acted long before now."

"Then perhaps I'm here out of curiosity? To see the man my brother was so enraptured with?"

"Even then, you would've come far sooner. Moriarty, for all that he was, was hardly a patient man and I'm assuming that neither are you."

"I'm hardly a man."

"No, but a twin must carry many of their counterpart's traits. Personality is a great deal genetic."

Her smile grew wider. "Twins, hmm? Not simply a brother and sister near in age?"

"Possible, but unlikely. You share too many of the same mannerisms, the same-" He paused, searching for a word to describe that unmistakable yet undefinable and definitely irreplicable thing that was their eyes and the way they lit and the way their words shaped and slipped from their mouths, but coming up empty.

"A speechless Sherlock, what a rare treat." She grinned openly now. "Tell me, Sherly, did my brother ever render you into such a state? Or am I special?"

"You seem to know quite a lot about me already. Did you and your brother rent out a small flat in the East end together then, or were you merely dedicated pen pals?" Sherlock quipped in return.

"Nobody writes letters anymore, Sherlock. It's all texting and those funny little faces and,"

"Emojis." He cut her off. At her questioning gaze, he clarified. "That's what those funny little faces are. One of John's girlfriends used to use them obsessively."

She chuckled. "You deemed that piece of information vital enough to store but not that the earth revolves around the sun?"

"It seems more relevant." Sherlock gave a tight-lipped smile in return. "But none of this has answered my original query, has it? Nor any of the ones that followed."

"Perhaps I just like playing with you." She sat back in the chair, strumming her fingers on the arms. "It did sound like Jimmy had great fun doing the same."

"But that's not why you're here either. If it were, you wouldn't have introduced yourself. You would've just started a game."

"Quite probably, yes."

Silence settled over the flat, only interrupted by the occasional strum of her half-gloved fingers and the occasional rattle of an experiment currently bubbling on the kitchen table.

"I'm here to thank you." She finally said.

"Thank me?" Sherlock's brow furrowed in confusion. Of all the many possible motivators he had considered for her visit, gratitude was not one of them. "For what? Burying your brother for you?"

"Seeing as how that was mostly your older brother's doing, no. He did have very good taste, though. The headstone is quite," She trailed off, searching for words. "Sophisticated."

"Yes, he got me the same one."

She laughed again, before ungloving her right hand and steepling her fingers beneath her chin; it was the first action Sherlock had seen demonstrated solely by her and not also by her brother. "No, Sherlock. I'm here to thank you for something far more recent."

Sherlock's eyes twitched as his mind raced through all the events- those that could be considered recent, in context, that is- analyzing them and subsequently discarding them as possibilities one by one. It didn't take long to discover to which she was referring.

"Magnussen." He said.

"The Napoleon of blackmail." She replied. "I rather like that nickname. It's quite an apt description."

Now it was his turn to smirk. "Had something on you, did he then? Something quite important it seems."

"What he had was," She trailed off again, seeming to enjoy the way she could make Sherlock hang onto her words in anticipation. "More than an inconvenience, but not one great enough for me to go through the trouble of killing him myself."

Sherlock examined her. "I think you're lying." She had no visible tell- she was far too good a lair for that- but Sherlock was fairly confident calling her bluff without one.

"Oh? About which part?"

"Whatever Magnussen had on you was substantial. If I hadn't killed him when I did, you would've done so- or at the very least attempted to do so- soon after. He knew a secret, and not about you. About your brother. About Jim. One that you were very, very determined to keep."

"Jim was hardly a man to be brought down by a secret."

"Not alive, no. But dead, well, that's an entirely different matter." Sherlock stood, slowly pacing before the fireplace. "Jim Moriarty had resources to outnumber Magnussen's own. He could've fended him off- not necessarily easily but adequately- so long as he was alive. After his death though, Magnussen became a liability. An annoying one at that. Locked up in his golden tower, all that information filed neatly away in that impossibly large brain of his. Untouchable."

Sherlock turned back to her with a slight smile. "Well, he wouldn't have been so untouchable had I not dismantled your brother's network of allies."

The woman grimaced. "Yes, that was quite impressive, I'll admit. Especially your work in Serbia."

Sherlock waved her off. "But you had your own network, surely. You could have gotten to him. Could have killed him. If Mary and I could infiltrate his tower, then so could you. Which means he had a failsafe in place. Something that prevented you from being in any way responsible for his death."

He began to pace more fervently now, his mind leaping and grasping at connections before discarding them as immaterial and racing for the next one, each time coming up empty and at a loss.

The woman watched him, silently admiring. She could see why Sherlock caught her brother's eye. Tall and wild eyed and wild haired and just slightly mad, he was her brother's picture-perfect antithesis. She caught herself wondering, as her eyes followed his rapid pacing and ears pricked up at his breathless mumbles, what would've become of him and Jim had they met under different circumstances, had one not been on the side of the law and the other the lawless. They would've been great friends, she thought. Terrifying, but great.

She knew he had forgotten she was there, watching him. Normally, he wouldn't have let himself be this vulnerable, this unguarded- not while those eyes watched him, at least. But she knew he would be. She had chosen her timing carefully. He was in the beginning stages of withdrawal. He could still feel the most recent concoction of drugs racing through his veins, making them prickle with desire and his brain seem maddeningly slow. He was undone, messy, and foggy. More importantly, he wouldn't remember this meeting all-to-well. Perhaps he'd remember it enough that, were he to see a face similar enough to her own in passing, or perhaps see the same dress worn by another woman on the street, his memory of this moment would be jogged and he would suddenly be aware of her existence. But until then, he would remember only her eyes, only her smile, only the way she tilted her head and the way she laughed and the way her words shaped and slipped out of her mouth. He would remember all these things as her brother's, remembering Jim's face and not her own- for truthfully they were near enough the same.

"Sherlock, why don't you sit down," She said, her tone familiarly bored and patently lyrical. "Before you hurt yourself."

He glanced at her irritably. "I was almost there, before you interrupted me."

"No, you weren't." She grinned. "You're in far too deep, Sherlock. So you should sit down, Sherlock, before you fall."

The word seemed to grab his attention, and- for once- he obeyed instructions.

"Not that the fall would hurt you, Sherlock." She leaned forward, slowly drawing an ungloved finger down his cheek. "Falling never could."

"No, just the landing." He drawled, his eyes blearing in and out of focus.

She got up, pulling on her gloves and smoothing out the lines in her dress as she did so.

"It's a shame I can't stay longer, Sherlock, but you know how it is. The world keeps on spinning, spinning, spinning." She moved towards the man beside her, whose face was buried in his hands. "It is spinning, isn't it Sherlock? Spinning round and round and round. It's spinning so much it's blurry. The floor is tilting."

Sherlock looked up, eyes desperately trying and failing to refocus on the face before his own. "You- what did you-"

He was cut off as he fell forward, slumping against the woman's outstretched hands.

Gently, she leaned him back in his chair, sweeping his curls away from his sweaty forehead.

"See, Sherlock, you should've learned to make your own tea. Mrs. Hudson isn't nearly attentive enough when she's making it. It would be far too easy for some to," She leaned in, whispering in his ear. "Slip something in."

She sighed, moving back and studying the man. Sherlock could only see the outline of her form- a black stain, leeching ink as she moved. He tried desperately to raise his head, but it was as if all the bones in his body- the vertebrae in his neck, the twin bones in his forearm- had left, leaving him limp and unable to move.

"Now, now, don't get yourself all worked up. It's just a sedative." She frowned, "A little more powerful than I would've liked, but you've built up such a high tolerance that I had to make an exception. You'll remain conscious for another three to four minutes. After that, you'll likely sleep for eleven to sixteen hours- it so highly variable- during which you'll experience involuntary movements of the legs and rather vivid dreams."

She leaned back in, close enough that Sherlock could feel the warm moisture her breath left on his ear. "I hope you'll dream of me." She pressed a gentle kiss against his cheek before pulling back, her gentle curls falling against his cheek and tickling the skin much in the way her lips had just done.

"You were right, of course, when you said Magnussen had a failsafe." She continued. "He was smart enough not to meddle in Jim's affairs- he knew Jim could've crushed him beneath his shoe. But after Jim died, well, he figured it was his turn to reign."

Sherlock watched as her blurry shape moved over to where he knew his skull resided on his mantle.

"But he wasn't Jim, and even his massive head couldn't hold up the weight of Jim's crown." She paused, and he heard the skull rattle as she picked it up. It shouldn't have rattled. "I knew he'd fall, one way or another. And I also knew that, unlike you, Magnussen couldn't survive it. That's the weakness of men like him. They climb so high that, should they lose their grip, they stand no chance of regaining it." She paused again, and he could hear another rattle. "Especially were someone to push them."

She reverently stroked the zygomatic arch of the skull, before returning it to its place on the mantle. It didn't rattle.

"As you said, I'm hardly patient. Watching him up in his golden tower was getting so boring." She drew the last word out with a sing-song contempt. "Imagine how thrilled I was to find out that it was you who pushed him off of his tower. You, the apple of my brother's eye, took care of the thorn in my side.

"So I did come to thank you, Sherlock. Really, I did." She neared him again, and once she came within a hairs distance he could see a small, cylindrical object clutched in her black-clothed fingers. "But I admit I was somewhat more motivated to get his little failsafe back from where he so cleverly hid it."

She patted his head, just as gently as she had touched him before, as if he was a precious thing to be handled with the utmost care. And in her eyes, she supposed he was. Sherlock Holmes was a precious thing, a thing to be obsessed over and played with and entertained by and a thing to be hurt but never permanently- never seriously. He was a precious thing, to be loved and touched gently at the risk that he'd crack and when he did she'd put him back together again treating each piece just as gently as the last. He was a precious thing, to possess so entirely and protect so totally, at the risk he'd burn. He was her brother's most precious thing, and so he was hers.

"You'll be hearing from me, Sherlock. After all, neither Jim nor I could cope with an unfinished melody. And, I suspect, neither can you."