This is the pool scene at the end of my favorite episode of Sherlock with my OC, Sherlock's adoptive daughter Karrine, who used to be abused. She's been with Sherlock for a year and a half. Goes with my other stories, except pretend Comets didn't happen and take out references to it from the other fics.
"I'm going out, Sherlock." Karrine, 8 and a half, said cheerfully.
"Really, where?" He asked, John looking up sharply.
She shrugged. "Thought I'd buy some milk, get some boba…" She gave another shrug, and waved before leaving the flat.
"You didn't give the plans to Mycroft, did you?" John speculated flatly once the door closed.
Sherlock typed into his website, 'Found. The Bruce-Partington plans. Please collect The Pool. Midnight.'
"No, I'm using them to flush out the criminal."
"What?! Even you can't be that reckless!" John cried incredulously.
"Right?" He added weakly.
The doors to the pool clicked behind the duo.
"Alright! I have the plans. That's what you wanted, right? Making me dance around, to distract me from this." Sherlock flashed the drive around, John groaning beside him. "Come on out!" Sherlock finished.
A door opened and a familiar little girl with curly black hair stepped out.
"Now this is a turn of events, isn't it?" Karrine asked, undoing the buttons on her pea coat.
"Karrine, what…" John started, watching with wide eyes.
"What are you…?" Sherlock started, the words dying on his lips.
"You don't know how to leave well enough alone… so I took one of your most precious things." She opened the coat to show them the explosives strapped to her skinny, frail chest, shuddering slightly as the red dot floated over her.
"What would you like me to make her say next?" Sherlock quickly scoped the room, gritting his teeth.
"Smart, isn't she? She was smart enough not to scream. Dumb enough to not listen to me when I told her to do something. Had to put a shock collar on her." She pulled the coat down a little so they could see the shock collar.
"Leave my daughter alone!" Sherlock cried.
"Karrine, sweetheart, are you alright?" John asked, forcibly calm.
"She knows better than to answer without me saying so. Every time she doesn't listen, or you two don't listen, the power goes up by 5. If you do anything really bad, I'll stop her heart." Her voice cracked at that.
"Just like I did little Carl Powers. I never liked him. He laughed at me. I'll start the power at 20. Don't worry, I won't shock her until you do something naughty."
"Show us your face!" John yelled angrily.
"Who are you?!" Sherlock hissed.
Silence settled on them, until a new voice came from the corner.
"I gave you my number. Thought you might call."
He slowly walked closer. "Is that a British Army Browning L9A1 in your pocket, or are you just pleased to see me?"
Sherlock pulled out the gun, pointing it at Moriarty. "Both."
Karrine giggled slightly at the dirtiness of what he just said, and Moriarty shushed her.
"Jim Moriarty. Hi." He paced slowly as Sherlock leveled the gun.
"Jim? Jim from the hospital? Oh, did I really make such a fleeting impression? But then, I suppose that was rather the point."
Sherlock and John looked to the red dots on Karrine's chest quizzically.
"Don't be silly, someone else is holding the rifle, I don't like getting my hands dirty."
Moriarty smirked. "I've given you a glimpse, Sherlock, just a teensy glimpse of what I've got going on out there in the big bad world. I'm a specialist, you see." He stepped forward and put a hand on Karrine's shoulder.
"Like you."
Sherlock glared. "Dear Jim, please will you fix it for me, to get rid of my lover's nasty sister?" He said slowly, then faster, "Dear Jim, please will you fix it for me to disappear to South America?"
"Just so!" Moriarty smiled almost coldly.
"A consulting criminal." John whispered.
"Brilliant." Sherlock said softly.
"Isn't it? No one ever gets to me. And no one ever will."
Sherlock cocked the gun. "I did."
"You've come the closest. Now you're in my way!"
"Thank you."
"Didn't mean it as a compliment."
"Yes you did." Karrine said softly." Moriarty shrugged. "Yeah, ok, I did. But the flirting's over Sherlock." He said the next part in sing song.
"Daddy's had enough now~!" He went back to speaking normally. "I've shown you what I can do. I cut loose all those people, all those problems, even 30 Million quid just to get you to come out and play." He let go of Karrine's shoulder, finally, and said, "So take this as a friendly warning… my dear. Back off."
He stepped closer to Sherlock. "Although I have loved this, this little game. I can't believe you didn't realize just who I was playing with. Playing Jim from IT, playing gay."
"Are you sure it was playing?" John asked venomously.
Moriarty glared. "Don't make me shock her."
John quickly backed down.
"Did you like the little touch with the underwear?"
"People have died." Karrine said softly. Moriarty turned to her, angrily. "That's what people DO!"
She flinched.
"I will stop you." Sherlock said coldly.
"No you won't."
"Are you alright?" Sherlock asked his daughter softly.
Moriarty stepped closer to her. "You can talk, Karrine." He said, overly sweet.
"Go ahead." Moriarty stepped away from her a little bit.
"Yes, daddy, I'm alright." She whimpered.
"Take it." Sherlock stretched the flash drive towards Moriarty.
"Huh? Oh, that! The missile plans." He kissed them and looked up at Sherlock for a second.
"Boring~!" He sang, tossing them into the pool.
"I could have gotten those anywhere."
Karrine suddenly lunged at Moriarty, knife pressed against his throat. She was disadvantagely short, however, and had to hold on tightly with her legs so she wouldn't fall.
"You guys have to run!" Moriarty laughed. "Good! Very good!"
"If your sniper pulls that trigger, we both go up, James Moriarty. AND I have a knife to your neck." She hissed in his ear.
Moriarty wasn't angry. "Wow, isn't your daughter sweet. I can see why you bring her to cases and teach her so much."
Karrine realized it before it happened.
She slowly let go and threw the knife into the pool. "I showed you my hand there, hadn't I? The sniper could have just trained his gun on one of them, ah, stupid!" She hit her forehead with the heel of her palm and glared at Moriarty.
He brushed off his suit, muttering something like Westwood, and asked, "Do you know what happens if you don't leave me alone, Sherlock, to you?"
"Oh, let me guess. I get killed."
"Kill you?" Moriarty repeated, grimacing almost playfully. "No, don't be obvious, I mean, I'm going to kill you anyway, someday. I don't want to rush it though. I'm saving it up for something special. No, no, no, no, no. If you don't stop prying…" He looked Sherlock over.
"I'll burn you. I'll burn the HEART out of you."
"I have been reliably informed that I don't have one." Sherlock said coldly.
"Oh, we both know that's not true at all." He looked to John for a split second, then turned to watch Karrine, then back to Sherlock.
"Well, I'd better be off. So nice to have had a proper chat."
"What if I was to shoot you now, right now?" Sherlock asked.
"Then you could cherish the look of surprise on my face." He made a surprised look, then smiled.
"Because I'd be surprised, Sherlock, really, I would. And just a teensy bit…" He looked around him at the three. "Disappointed." Karrine looked away from him.
"And of course you wouldn't be able to cherish it for very long. Ciao, Sherlock Holmes, I'll be back, for the little girl, someday."
"Catch you…" he made sure to keep the gun trained on the departing figure. "Later."
"No you won't~!" He sang, door closing behind him.
John immediately started to take off the bomb as Sherlock demanded to know if she was alright. She didn't answer the first time, and Sherlock asked louder.
"F-fine..." She fell to her knees and sank into John.
"Oh Christ… are you both alright?" John nodded as Sherlock paced, gun in hand. "Yeah, fine, fine, fine." He took a breath.
"You shouldn't have tried to sacrifice yourself for us!" Sherlock wasn't really mad, he was really relieved she was alive.
"At least we're alive." John whispered.
Karrine stood and noticed the laser dots on John and Sherlock.
"Oh…" she was really relieved the bomb and shock collar were off. At least. And no laser was on her, so…
"Sorry, kiddies! I'm SOOOO changeable. It is a weakness with me, but to be fair to myself, it is my only weakness. Oh, boys, you two can't be allowed to continue. Don't worry, I'll take good care of Karrine for you. I would try to convince you, but everything I have to say has already crossed your mind."
Karrine grabbed the gun from Sherlock and pointed it at the bomb, glaring. "Then this must have crossed yours."
The 2, Karrine and Moriarty, seemed to have a conversation with their facial expressions.
Just as Karrine was going to sacrifice herself again, his phone rang.
"Could I get that?" She stared a second, then nodded.
After the (morbid) conversation, he started to walk away, the laser dots leaving.
"Sorry, bad day to die. He walked out of the pool, continuing his conversation.
"Someone doesn't want us to die." Sherlock speculated, grabbing the gun and leasing them out.
"We're going to Lestrade to get you protection." John told her as she got on Sherlock's back, falling asleep in his curls quickly.
"Do you think he'll do something similar to what he did to you to Karrine?" John asked softly.
Sherlock hailed a cab to Scotland Yard.
"If he does, he'll die trying."
*At Scotland Yard, A Few Hours Later*
Lestrade stepped towards Scotland Yard, mouth open wide at the scene in front of him.
Karrine was snuggled into Sherlock's chest, asleep, and John was asleep on Sherlock's shoulder. They were propped up against the wall.
Sherlock was the only one awake. "We forgot what time it was. We've been waiting for hours for you to get here." He woke up John but carried Karrine in her arms, still snuggled into his chest.
"Moriarty has grown… infatuated with my daughter. She needs protection."
Lestrade went grim and nodded, leading them inside.