A/N: Don't ask me where this came from because I have no idea. Just me toying with a different ending for HLV than what we were given. Previously uploaded on tumblr, but substantially revised since then. Basically Sherlock & Mary brotp-ness.
Sherlock came to with a start, looking wildly around the room - his parent's kitchen? How had he returned here, when he and John had been heading out to meet Magnussen's helicopter? A quick look around told him that both Mycroft's laptop (unimportant) and John (very important) were missing. He tried jumping to his feet, only to stagger a bit and nearly fall when his legs refused to cooperate; whatever drug he'd been given (he'd had nothing to eat or drink, what was the delivery method, who had done this) was clearly still affecting him. He only just managed to stop himself from collapsing to the floor by slamming his hands on the wooden table top.
As if that sound was a signal someone (a far too familiar someone) had been waiting for, he heard, "He's in here, Sherlock. With me."
Once he was certain his legs would do as instructed, Sherlock turned and headed for the door to his parent's sitting room. There, on the sofa, decidedly not unconscious, was Mary Watson. John lay with his head on what little of her lap there was considering the current size of her abdomen, and she was stroking his hair. Sherlock darted his eyes around the room, assessing any potential danger, wondering briefly if he'd been wrong to forgive and trust Mary, when she spoke again. "He'll be fine, Sherlock. Everyone will be fine, I promise. This isn't an attack, unless you want to call it an attack of common sense."
"What happened to the helicopter? How did you drug us?" Sherlock demanded, keeping his gaze firmly focused on Mary.
"The helicopter's gone on to Appledore, as scheduled, with Mycroft's briefcase. His pilots were replaced by - well, let's call them freelancers who are very skilled at infiltration, shall we? As for drugging you…" She reached down between the sofa cushions and held up a small, ornately carved wooden tube. "Blow gun," she said succinctly, waggling it between her fingers before tossing it to him. "One dart apiece for you and John." She glanced down at her husband with a fond smile before looking back at Sherlock.
He caught it in one hand, clapping the other to the back of his neck and probing for the small wound...there! He could just make it out. "Why?" he barked out, the most important question, the one he should have asked first. He slipped the blowgun into his jacket pocket, intending to study it closely later on.
"To save you from making the same sort of idiotic mistake I made by trying to take Magnussen down by myself," she replied, quite calmly. "I called in a favor from the one former ally I trusted not to take advantage of me - and if she's done what she's supposed to have done, then my mobile will ring in a few minutes with good news."
"And if this woman instead decided to betray you?"
Mary shrugged. "Then honestly, Sherlock, I won't be in any worse position than I am now. Magnussen already knows who I used to be - "
Sherlock cut her off with an impatient huff. "No, if this woman decides to betray you to the people Magnussen is threatening to expose you to."
"She won't."
There was a tone of absolute finality in Mary's voice, one that brooked no argument. He was inclined to argue anyway, but the way Mary was looking at John, the way her hand rested on the mound of her stomach, gave him pause.
"He's forgiven me," she said softly, almost too softly to hear. "John has actually forgiven me, Sherlock." She looked up and he saw the shimmer of tears in her eyes, heard the wonder in her voice. "He tossed my history onto the fire without ever having read it; when I told him he didn't even know my name, do you know what he said to me?"
"I would deduce it to be something along the lines of 'Mary Watson is good enough for me'," Sherlock replied, a smile of his own touching his lips.
Before Mary could do more than nod in response, her mobile rang. Sherlock raised an eyebrow at the old-fashioned tune that blared out, recognizing the melody even without the lyrics as Good-Night Irene. Interesting...
"Is it done?" Mary asked. Silence on the other end, at least to Sherlock's straining ears, but Mary's intent expression cleared and she smiled. "Good. So now we've repaid each other, yes? No more debts between us?" Another longish pause, during which Mary's smile only deepened, even turning into a chuckle as she said, "Sorry, love, not even for old time's sake, happily married now and a bit too pregnant for your kind of fun and games. But have a good life, all right?"
She listened again, smiled broadly, then hung up the phone, returning her attention to Sherlock. "Right. Magnussen is in possession of your brother's laptop. Apparently he had someone drug everyone here, stole it, and has made threats against the household. You'll find a message on your mobile from him, from Appledore, that can be turned over for evidence."
"Fingerprints?" Sherlock asked. Regarding the laptop, not his mobile, but he was confident Mary was quick enough to understand him. Really, when would he stop underestimating John's wife?
"Lifted from Magnussen's office and planted on the keyboard and other strategic locations, so even if he doesn't handle it or open it, it'll look like he did. MI-5 and the police are already on their way," she added. "There, as well as here." Right on cue, Sherlock heard the sound of sirens in the distance, quickly coming closer.
"Magnussen is still a threat, even with Mycroft's stolen laptop in his possession," Sherlock reminded her. "This is a stopgap measure at best. As soon as he's arrested he'll only have to make one phone call to get himself released. Too many people are afraid of him." He paused, studying her intently. "But you're not, not anymore," he said slowly. "And not just because of this. Why is that, Mrs. Watson?"
"Because I know the truth about his vault now," she replied, sipping her tea. Drugged, no doubt; far better for them all to be found unconscious than any one of them awake. He'd have to take a rather heftier gulp himself and soon, but he needed to hear what she was going to tell him. "It's not an actual vault. He has nothing in the way of physical evidence, Sherlock. It's all here." She tapped the side of her head.
"Mind palace," Sherlock breathed, impressed and chagrined at the same time. He always missed something, and this was one hell of a huge miss. "But he still knows who you used to be…"
"A fact which is useless to him now. A certain mutual acquaintance just reassured me of that."
He examined her closely, then gave a sharp nod. "I see." And so he did; no matter what happened next, Magnussen was no longer any threat to Mary or John. Good.
The wailing sirens grew closer; by the sound of it they'd turned down the lane leading to his parent's home. Quickly he crossed over to Mary and removed the tea cup from her hand. "I'll just have a few sips and join you all in la-la land," he said as her eyes drooped. "But when this is all over, Mary, you and I are going to have a little chat about keeping one another in the loop when it comes to situations like this." He smiled and sipped the tea, offering her a small salute. "Because I have the feeling, when we're not working at cross purposes, that you and I would make an admirable team."
"Couldn't have said it better myself," Mary mumbled, her head dropping forward as the drugged tea took effect. Sherlock continued to sip from the china cup, not stopping until he felt his legs turned to rubber and collapsed onto the carpeted floor in front of the grate. The last thing he did before unconsciousness claimed him was to toss the wood blowgun into the fire...right next to the thumb drive labeled "A.G.R.A".
Mary had saved them all - Mary and, as he would later discover, not only Irene Adler, but Molly Hooper as well.
But that was a tale for a much later date.
~Fin