John realized that something was awry the moment he stepped down the final stair into the living room of the flat to find it spotlessly clean. Every paper, every months-old clue tacked on the wall, had been either straightened or completely hidden from view, and the doctor nearly went back up to his room and into bed at the sight of it. Sherlock was in front of the far window, playing something light and energized on his violin, completely ignoring him.
"What's going on, then?" John sighed, rubbing his forehead as he walked and plopped down in his chair.
"Visitor. Arriving soon, I'd wager. I would change if I were you, she's hardly one for lateness."
"Vis—she?" John blinked at him, but the detective kept his darkly-suited back to him, still playing the tune without a pause. After a moment of baffled questioning that was not in any way answered, he scoffed and trudged up the stairs to change. Once safely back into his bedroom, he sat on his bed and frowned, thinking. Sherlock certainly never had visitors whom he invited over, and he certainly had never cleaned in expectation of them. He hadn't even believed Sherlock could clean, since he had spent the better part of their living together picking up after the man like a mother hen. Shaking his head, he sighed and pulled a tan colored jumper over a deep green button-down, taking a hint from Sherlock's outfit that he should probably at least look decent. Pity, he had planned on spending the majority of his day drinking tea in his pajamas. Teeth and hair brushed, trousers buttoned, trainers tied to his feet, he came down the stairs and was again struck by how spotless the room was. Sherlock hadn't moved, of course, still playing agitated tunes on his violin.
Was he nervous? John was baffled by the thought, having never seen Sherlock show such obvious concern toward a person's opinion, even his own. Overcome by curiosity once more, he opened his mouth to ask again when a light rapping sounded on the door. John, noting that Sherlock made no move to answer it, sighed and pulled open the door, and nearly dropped his jaw at the sight.
The woman standing in front of him was hauntingly familiar, though he was absolutely positive he'd never seen her before. He would never forget such a distinctive face. She was tall and thin, her body seeming to buzz with energy despite her stillness, her angular face framed by a bob of glossy chocolate brown curls that made her wide crystal-like gray eyes shine brightly. Her full pink lips were pulled into a dazzling grin, "You must be Doctor Watson!" she cooed, her high voice ringing with a slight American accent, as if she had been abroad for many years, and all at once she had enveloped John into a tight hug. The instant the thin arms wrapped around him, he realized. She looked exactly like Sherlock. "Dear lord, Mycky told me you were acceptable but he didn't ever mention how handsomeyou were! And a soldier too, good lord." She tucked a curl behind her ear before her eyes slid to Sherlock. "Sherly!" Her high voice rose impossibly to a squeak, and John would have been tempted to cover his ears at the sound had he not been so distracted. Sherly? Mycky? He stared at her in bafflement as she skipped across the room to his flatmate, who put his violin down and turned to her with an honest-to-god smile, accepting her hug.
"Katarina." He replied, deep voice warm, and she smacked his arm playfully. He smirked, the two of them seeming to exchange some sort of silent conversation, half of which John couldn't see, as the girl's back was to him. Finally, Sherlock's gray eyes went back to his baffled face, and he straightened. "John, allow me to introduce my little sister, Katarina."
"Little sister." She scoffed, turning to face John again, "I'm only two minutes younger, but he never lets me forget it. And please, call me Kate." Her smile was dazzling, and John was momentarily distracted.
"Sister." He finally choked, "You have a twin sister that you've never mentioned?" John glared at Sherlock, who gave an exasperated sigh.
"That's my fault, darling," Kate interjected smoothly, placing a light hand on her brother's arm to cut off the argument he was clearly about to make. "My existence is need-to-know only. My brothers do quite a job of protecting my anonymity. This is my first time back in the country in…oh, what is it, Sherly? Fifteen years?"
"Sixteen." He corrected quietly.
"Oh, quite right. The Tête de Femme robbery." Her expression became wistful.
"Sorry, why do you need to be anonymous?" John asked, completely in awe, realizing he was staring at her as he caught Sherlock glaring at him in his peripheral vision. The tall man placed a hand on the small of her back and led her to his own armchair, which she sat in gracefully, curling her long legs under her despite the short length of the charcoal-colored pencil skirt she was wearing.
"On record, I am a travel photographer. I have a blog and everything, it's quite extensive. I did this piece on food of the American south that was divine—" she cleared her throat, realizing she was trailing off, "Er, right. But I actually work for Mycroft, doing undercover research abroad. Prevent assassinations, recovering stolen Picasso works, things Sherly deems 'boring', you know." She gave John a conspiratorial wink, and Sherlock rolled his eyes.
"Ah. Right." John nodded, sitting in his own armchair across from her.
"You are unsurprised." She observed, smirking.
"You're a bloody Holmes, aren't you?" He replied before he could stop himself, but she laughed lightly.
"Yes I suppose the lot of us are rather addicted to danger. And sticking our noses where it doesn't belong." She sniffed, shrugging, "Sherly, dear, be a doll and get me some tea, would you?" she purred, turning her gaze to her brother. Much to John's disbelief, he actually nodded and strode into the kitchen, leaving the two alone. "So, Doctor Watson—"
"John. Just John." He interjected, flushing.
"John," she smiled sweetly, "Sherly has told me so much about you. I feel as though we are friends already." John was struck once again by her eyes, by how bloody similar she looked to his flatmate, though her personality was completely Sherlock's opposite. She was charming, her smiles easy, her voice high and dripping with genuine interest. Still, he couldn't get over the feeling that she was studying him with her conversation the way her brothers deduced things about him from his physicality. It was disconcerting.
"I wish I could say the same." He finally said lamely, and she shook her head, still smiling.
"Don't hold it against him. My brothers act disconnected from their humanity, but we'd do anything for each other." John frowned; he'd always assumed as much, at least from Mycroft, but it felt odd having it said out loud. He'd regarded the Holmes brothers' relationship to be a bit of an elephant in the room, knowing that they obviously cared about one another, but no one ever stating so outwardly. Sherlock made his reappearance then, placing a cup of tea in his sister's small, lithe fingers. John noted that it seemed to have more milk than actual tea in it, much like Sherlock preferred. This was too odd.
"I assume you had a reason for coming here." The detective said brusquely, standing next to her chair. She took a sip of the tea and placed it neatly back in its saucer on the table beside her before nodding, leaning forward to pluck the mustard-yellow leather tote bag she had brought with her off the floor. John didn't miss the little CC's on the patterned red scarf tied fashionably to one of the handles; exactly how much money did this bloody family have? Enough to where Sherlock certainly didn't need a flatmate. He huffed and crossed his arms, watching with interest as she pulled a black folder from the bag and handed it to Sherlock.
"He's on the move." She sighed, watching as Sherlock flipped through what looked like large photographs. "Those were taken in Miami. He boarded a plane to Moscow. I had Danielle attempt to intercept him, but he got in an unmarked vehicle and disappeared into the night upon arrival. Completely off the map."
Sherlock scoffed, "Why would you send her?"
"She happens to be my best agent—"
"Bloody flirt, that's what she is. Idiot."
"And my best friend." Kate added over her brother's skulking accusations, glaring at him. The two scowled at each other before he turned his attention back to the photographs.
"You believe he's headed back here." He finally said, and she nodded.
"Oi! As clever as you two are, mind letting me in here?" John snapped, growing frustrated. Two pairs of crystalline eyes turned to him, and he shifted uncomfortably.
"Moran, John. Keep up. I did tell you I had people in America trailing him." Sherlock rolled his eyes, tossing him the folder.
"When you said you had people trailing him, you didn't think to mention that person was your twin sister?" John accused, still bitter, as he flipped open the folder and went through the pictures. Most of them were slightly blurred images of a tall, thickly muscled blond man travelling through what seemed like a large airport.
"Is he always so angry?" Kate whispered, looking up at Sherlock, who grimaced.