The man had nodded when suddenly the door burst open and Sherlock came tumbling through, and the man's eyes went wide. Within half a second he had darted behind John to press the cold tip of a knife to the back of his neck. "Detective," he murmured, and John winced as the knife bore down a bit against his top vertebrae.
Sherlock froze, and John could see Lestrade behind her. John took a deep breath, trying not to panic, trying not to notice the tell-tale sign of his left hand being utterly still.
"It's okay," he murmured. "You need to let me go, and I'll take care of the detective, remember?"
He felt the knife lighten a bit, and Sherlock straightened slightly, brushing a curl out of her eyes. "What-?" she began to ask, but John shook his head.
"You need to cut my arms free," he said quietly to the man above him, but he didn't move, and John's eyes widened as he saw who stood behind Gregory on the stairs, and Sherlock noticed - Sherlock noticed everything - and she whirled, pulling Lestrade into the room and landing a solid punch on Ms. Pillington, who doubled over with a groan. Sherlock followed it up with a quick chop to the pressure points in the neck, and then Lestrade realized what was happening and helped catch the now-dazed woman. John felt the man behind him start to panic, and the point of the knife broke skin, and he felt the adrenaline in his veins, his pulse pressing on the multiple zip-ties that held him to the chair.
"You need to cut my arms free," he repeated, and the tip left again, and John could see the fear in Sherlock's eyes as she saw the murderer make his decision. And then the ties around John's hands were free, and he pulled his arms forward, rubbing his wrists, wincing. He looked down at his feet.
"Do you mind getting those, too?" he asked, and looked up, but the murderer still had his eyes on Sherlock.
"Detective first," he said, and John looked over at Sherlock, who was looking at John, and John suddenly realized he'd been taken captive - again - and yet he was the only one who seemed to have any control over the room.
"Sherlock, this is - I don't know your name," he confessed, and the man frowned, and he quickly moved on. "Never mind. Ah, this is Sherlock. Sherlock, um, he -" John motioned toward the murderer, "is slightly manic depressive, and I'd say he has some brain damage as well. He's been given some volatile medication, and I think Ms. Pillington has been pulling some strings to, ah, make him her personal murderer. Or something like that. In any case, he just needs help and weaning off his meds, he's not actually - well, I don't think he's a horrible person, he didn't want to kill me, anyway, and I told him that if he let me go I'd make sure you didn't hurt him, so I'd really appreciate it if you were, ah, nice." John shut his mouth with a snap as he realized he was rambling and Sherlock was looking at him with a growing smile of amusement, while Lestrade was gaping openly, one arm still restraining Ms. Pillington, who was now beginning to struggle slightly.
"David Arborson," Sherlock said, and the man jumped behind John, but Sherlock came forward with a hand out for a handshake. "I believe. It's nice to meet you."
The man - David, apparently - switched hands for the knife and stepped forward to take her hand, looking confused. "Hello," he murmured, and Sherlock smiled - an actual, genuine smile, John noted.
"I'm not about to hurt you," she said, and gestured to John. "However, he's my friend, and I bet his legs are hurting him."
"Right," David said, and bent for the knife, cutting John's legs free with a snip, handing both the ties and the knife to John once it was done, and John was once again struck with how childlike the man was when he wasn't angry.
"Thanks," he said, and David nodded, standing and bouncing in place with the barely-contained movement that seemed to keep him constantly pacing before. Sherlock noticed it as well.
"When I get like that," she motioned to his moving feet, "my friend makes me tea."
David looked at her, and John grinned suddenly. It was as good a cue as any, and he turned to Lestrade. "Did you see a kitchen somewhere in here?" he asked, and the Inspector nodded. "Upstairs, on the right."
"Right, then," John said, and nodded at the stairs, not wanting to make any movement toward David for fear it would be mistaken as an attempt to harm. "Would you like some tea?"
For a moment, David's eyes narrowed in suspicion, but then he nodded, and John headed toward the stairs, turning his back on the man in a deliberate gesture of trust; both that David was no longer going to harm him, and that Sherlock had John's back if he tried.
John put the knife carefully in a bag when they reached the kitchen, realizing it was evidence and, while smeared over with his own fingerprints, it was probably best to preserve it to some extent. Sherlock grinned when she saw what he was doing, probably picturing Anderson's face when he had to process it as evidence.
"Right," John said, grinning as Lestrade came in. He'd apparently gotten fed up with Ms. Pillington's attempts to break free of his grip, and had tied her up with his jacket. She looked furious, but as the collar was backwards against her mouth, she couldn't speak without getting a mouthful of fabric. "I'll just put the kettle on, then. David, why don't you take a seat, and we'll talk over what happens next, okay?"
David took a seat at the nearby counter, letting his legs bounce, and Sherlock hopped up to sit on the counter next to John, who ignored her and flipped the switch on the kettle that sat next to the sink. He rummaged through the cupboards, and found tea in the top of one. He had to jump to reach it, which made Sherlock snort, and he fixed her with a glare before switching off the kettle and pouring the tea, sliding the mug across to David while sitting down with his own.
"You'll need to take the teabag out in a bit," he said to David, who nodded seriously as he blew on it strongly, a bit of water splashing onto the counter.
"Right," John said again, realizing everyone in the kitchen was looking at him again, even Greg, which really wasn't fair, thought John, because he'd half expected Lestrade to take over once they'd gotten upstairs, just like he would at a crime scene. But apparently not, and so John sighed, twirling his spoon in his tea for a moment before looking over at David again.
"David, you're trusting me to help, and I can, but I need you to trust me," he began, and then smiled, realizing that David already had - he'd handed him the knife, hadn't he? The only problem was John had very little idea what to do; it wasn't as if he could promise David he wouldn't go to jail. He had been an accessory to murder, after all.
"Trusting Doctor Watson is always a good idea, I'm learning," came a voice from the door, and John looked up to see Mycroft standing there with his ridiculous umbrella in hand. "Hello, John. I hope you don't mind my interrupting your..." Mycroft looked around and wrinkled his nose slightly, just enough not to be distasteful, "...tea party," he finished, and John grinned.
"This is my friend, Mr. Holmes," John introduced to David, who was looking at Mycroft's umbrella with an expression of childish delight. It was amazing how quickly his boundaries came down once he seemed to decide everyone John liked wasn't going to hurt him. Lestrade, on the other hand, was gaping again. "Mycroft, this is David," he said, and Mycroft lifted an eyebrow.
"I was aware," he said, and came forward. "It's good to meet you, David."
"I haven't learned umbrella yet," David said quietly, and to John's surprise, Mycroft smiled.
"David, I have a proposition for you," he said, and David's eyes shot up to meet his. "I want to take you somewhere safe, where Doctor Watson can visit you when he likes, and you can learn all the letters in your dictionary, and people will take care of you. In return, I need you to tell me everything that's happened over the past month or so."
David looked at John, who nodded slightly, and then looked at Mycroft's umbrella again.
"Can I have an umbrella?" he asked, and Mycroft's smile widened.
"You may have an umbrella," he confirmed, and David nodded quickly, his legs bouncing faster - but this seemed more excited than manic, John noted happily.
"What am I going to do, then?" Lestrade complained, coming to his senses. "I mean, her I can explain, or at least try to," he said, gesturing to Sherlock unhappily, "but I can't explain someone just taking away my - a person!" He barely missed saying "suspect" in front of David.
"Indeed, you won't have to," Mycroft said smoothly. "I believe you'll find that when you get back to the Met your case will have been reassigned to the Home office, which you shouldn't worry about at all; it's all been taken care of. Think of it as a small thanks for the work you've done with my sister."
Greg was gaping again, and Sherlock rolled her eyes.
"Now, then. David, are you ready to go? I'm certain no one will mind if you bring your tea along," Mycroft said. David nodded, and Mycroft turned to go, but Sherlock hopped off the counter and grabbed his arm.
"Wait," she said stubbornly, and Mycroft turned with a sigh. "Where's the bug?" she asked with a frown, and Mycroft grinned, suddenly looking younger.
"I suppose you'll have to look," was all he said before extracting himself from Sherlock and leading David out to the black car John was certain waited outside.
"Just leave Ms. Pillington there, Gregory," Mycroft called back. "Your jacket will be replaced."
Lestrade looked at Ms. Pillington, who was glaring at him and trying to get free of the jacket. He'd pulled it on her backwards, thrusting her hands through the sleeves and zipping it, then tying the sleeves together behind her back so it made a makeshift straightjacket.
"That's my favourite jacket," he complained, and Sherlock rolled her eyes.
"He'll replace it with bespoke leather, Lestrade," she said, and Greg didn't look happy, but he pushed Ms. Pillington onto a chair and stomped out. John followed with a grin at Sherlock, who was frowning in thought.