I own nothing in this entire story. Only in my dreams could I hope to have control of these characters.
Sherlock gave a sigh of exasperation, watching the unwelcome intruder in her flat. "I already told you, I haven't finished yet. It's a complicated formula, but I've almost cracked it."
Her older brother narrowed his eyes. "Sister mine, you mean to tell me you've had over a month to find an antidote and yet you still have yet to?" Mycroft leaned on his umbrella. "My, you're getting slow."
Sherlock glared at him, but didn't acknowledge his words, instead focusing back on the experiment she had been running. Mycroft sighed heavily before turning and exiting the room, his footsteps echoing on the stairs a moment later. Not a few minutes later there was the sound of a door closing and a different set of footsteps coming up the stairs.
John entered the room, tilting his head to look back down the stairwell. "Sherlock, what's the matter with Mycroft? He seemed rather annoyed as he left-"
"Mycroft is always annoyed, it's a habit with him-" Sherlock spun around, her long curly black hair flying wildly around her face. "He expects me to finish an antidote in under a month when his own scientists haven't in years, the nerve-" She muttered, pacing over to the window. John just accepted the answer, knowing his opinion would be 'irrelevant'. He walked over to Sherlock's experiment, looking down at it tiredly.
"Do you really need to take this much room-" He reached out to move some of the half filled test tubes aside. "I'll just move them over a little, alright?"
Sherlock's head snapped up at that and she hurried towards John, a hint of worry sliding across her face. "Wait- Don't-" She jumped towards him, pushing him away from the table, but the warning was too late as John pushed aside the vials at the moment she spoke. A cloud of hazy smoke erupted into the air, almost fully engulfing Sherlock.
John started in surprise before rushing forward to try and see if his friend was alright.
Sherlock lay unconscious on the ground, her body shrinking down, smaller and smaller until she looked about 5 years old. The de-aged genius was absolutely tiny compared to the now extremely oversized clothes that surrounded her.
"This- no this-" John shook his head slightly, sure that he must be hallucinating, that there was no way his annoyingly troublesome flatmate was now a child, but when he looked again she still lay there, her small form shivering on the cold floor. He bent down, gently picking her up and bringing her over to the couch. As she was being moved, Sherlock let out a small whimper mixed with a cough, a small plume of smoke exhaling from her lungs.
When Sherlock was set down on the couch, she curled into herself making her already small form seem absolutely tiny. John draped a blanket over her before sitting on the edge of the couch, watching over her in concern. A few minutes passed without much event before Sherlock sat up suddenly with a small gasp.
The child scanned her surroundings in confusion and fear, jumping slightly when she saw John. "Who- who awe you and whewe am I? Whewe's C'oft?" She seemed unable to say her R's. Her eyes flashed over John, trying to find anything that would give her the answers she needed. John raised his hands slightly to show he meant no harm.
"I'm a friend, I promise-" He began, but Sherlock cut him off.
"I don't hawve fwiends-" Sherlock said firmly, "Who awe you?"
John tilted his head slightly in confusion, forgetting to answer the second question as he asked "You don't? Why?"
"Fweaks don't hawve fwiends." Sherlock deadpanned, edging away from John a bit as her eyes scanned the room for possible exits. "Who awe you?"
John bit down his anger at that answer, she way she said it was as though she had been told and told it herself so many times it was just normal, but he didn't want to scare Sherlock. "My name's John Watson." He said gently.
Sherlock studied him a bit closer. "You'we a doctow- you wewe a soldiew, but came home because you got shot?" She spoke softly, as if she didn't realise she was saying her observations out loud. John nodded softly, though he knew she wasn't looking for confirmation. Her eyes widened slightly as she realised she had spoken aloud.
"Whewe is C'oft?" Sherlock repeated her earlier question softly, looking up at John.
"C'oft- Mycroft?" John realised. "He was just here, I can call him if you want-" He took out his phone to call the older Holmes sibling, hoping maybe he would know what had happened. Mycroft answered after a moment or two.
"Doctor Watson, I trust you have a good reason for calling me so soon after my departure?"
"Mycroft, your sister- she's a child." John managed. "Not like usual, like physically a child." There was a pause on the other side of the line before the government official finally spoke.
"I'm on my way."