I do not own Sherlock or any of the characters. All hail ACD, Moffat, and Gatiss.

1.

It was the adrenaline, Sherlock sourly tried to convince himself, later on, after he and John had drifted into their evening routines. He ran through the scene over and over in his mind, desperate to… Well, he wasn't sure what he wanted to do with it.

The door to 221B slammed behind John, and they leaned against the horrible wallpaper at the base of the stairs, catching their breath, laughing without air, just convulsing with twisted grins until they could drag in their breath normally again. And Sherlock made the mistake of looking at John, and John caught his eye, and they lost it again, this time actually sliding down the wall together, unable to hold themselves up any longer under the weight of hysterical hilarity.

"Ohhh, my God," John gasped, wiping his eyes. "That was brilliant."

"Wasn't it?" Sherlock grinned, and then he looked at John again, and all of the breath he'd just gained back was stolen away again in the span of one heartbeat. John's cheeks were flushed, his eyes still bright and laughing. His hair was an utter mess. Sherlock felt something unfamiliar stir inside him, and rather than sitting and thinking on it, or doing experiments on it, or trying to rationalize it (and this is where he blames the adrenaline), he just acted on complete instinct, leaning forward lightning fast and placing his lips over John's, kissing him, hungry, digging—

And John pulled away. Didn't kiss him back, didn't reach up and weave his hands into Sherlock's hair. Just froze for a split second, overtaken by true, genuine shock, then pulled away.

"What are you doing?" John asked, most of the traces of laughter gone in a split second. Sherlock realized that he had done that, had chased away all the happiness in John's face and replaced it with confusion and more than a little fear. He'd done something wrong; no, something Wrong.

"I would have thought that would be obvious, John," Sherlock said acidly as he viciously shoved down the blush of embarrassment creeping up his neck.

John closed his eyes, knowing Sherlock was avoiding the question but also knowing he'd asked the wrong question. "Sorry, shouldn't have said that," he said through gritted teeth. "What I meant was, why did you do that?"

"I would have thought that would be just as obvious," Sherlock shot back as he got up, his long limbs shaking as the adrenaline drained away. He left John sitting there on the floor and climbed the stairs, two at a time as always, boiling with an anger he didn't understand.

"I'm going to bed," John announced, breaking into Sherlock's thoughts with surprising ease. Sherlock was curled up on the couch, his back to the rest of the flat. He analyzed John's tone. There was no malice or embarrassment tinting the words, just the complete exhaustion that came after an adrenaline rush. Sherlock deduced that John wasn't planning on bringing up the incident again, which made him feel… Confused. He didn't want to talk about it, not ever, no… But he at least wanted John to think about it, be just as confused and hurt and angry as Sherlock was so that he wouldn't have to wallow alone in it. But there was nothing in John's voice, nothing but tiredness, and so Sherlock made a sulking "Mmph" noise and burrowed further into the couch. He heard John sigh and walk toward him, setting something down on the coffee table, a mug with liquid in it. Tea.

"Goodnight."

Sherlock said nothing.

2.

John couldn't sleep. Despite the fact that he was nearly forty, for God's sake, and shouldn't be pegging it down alleyways after crazy sociopaths who tried to kiss him (not thinking about it, John's inner common sense sang out), he could not force his eyes to close. They stayed stubbornly open, taking in every detail of his immaculate bedroom. Suddenly, the room felt much too small.

He blew out an exasperated breath and checked the time. 2:27 a.m. He couldn't take it anymore. He threw back the covers and shoved his feet into his shoes, sneaking expertly down both flights of stairs and out the front door.

As he walked, breathing in the cool late-night London air, he finally let himself think about what had happened. They'd been laughing, yes, laughing as they crested the wave of the adrenaline rush together and then Sherlock had leaned in and all John's senses had failed him and he froze and let Sherlock actually kiss him for a second before regaining his wits and pulling himself away.

John knew Sherlock was, objectively speaking, an attractive person. He couldn't deny himself that truth. He was thin and composed and always in control of every muscle, and his hair framed his face in such a way that it made him look pale and angular, ghostlike. And he also had to admit to himself that he'd let his mind wander There, into the Territory That Must Not Be Named—what it would be like to kiss Sherlock, touch him in more than a friendly manner. He'd even had a dream once (NOT THINKING ABOUT IT, NOT THINKING ABOUT IT, his inner voice sang-screamed at him). But the thoughts had always filled him with something close to revulsion. He'd never had any trouble with grasping his own sexuality. He knew he was a straight man. He'd never had a problem with homosexuality, of course—anyone who did these days was either evil or brainwashed, he thought viciously, Harry floating in the back of his mind. He just knew he didn't swing that way, and he especially didn't swing that way toward his best friend.

And until today, he'd believed that Sherlock didn't swing any which way at all. And they'd been fine. It had all been fine. What had gone wrong?

John shook his head, trying to pry loose the images of Sherlock having sex with other men flooding his mind unbidden. His watch read 3:24 a.m. He'd been walking and thinking for almost an hour.

Sighing, he turned and trudged home.

3.

"Sherlock, we have to talk about it some time."

Sherlock was looking through a few cold case files that Lestrade had brought over. They hadn't had a case since he'd solved the one from last week, the one that led to the chase and the laughing and the kiss—

He shut down that part of his mind immediately and savagely turned a page in the folder he held, nearly ripping it in half as the paperclip clung to it with a stubbornness that rivaled his own. He ignored John's words and spent all his energy focusing on the case in his hands. Until it was snatched away. He growled, lunging, but John held him back easily.

"Stop—struggling—you idiot—Listen!" But Sherlock did not want to listen, and he never did anything he didn't want to do. "What if I let you kiss me?" John shouted, loud enough for Mrs. Hudson to hear, but he didn't care; all he cared about was stopping Sherlock from bowling him over. And it did stop Sherlock, right in his tracks, almost comically frozen as he reached for the folder in John's hand, one foot braced against the couch for leverage.

"Why?" Sherlock asked suspiciously, still poised in his awkward ballerina stance, hovering over John.

John steeled himself internally, determined to see his plan through. He was a curious man, and leaving anything at all in any shade of doubt lay far beyond his nature. He had to follow through with this, had to make absolutely sure of what he wanted and what he didn't. He supposed it was cruel to Sherlock, if Sherlock could be said to have feelings at all, but Sherlock was cruel all the time and never apologized, never seemed to realize the effect his flippancy had on the people who were subject to it. John figured Sherlock could withstand being part of an experiment of John's, after he'd been forced into so many of Sherlock's.

"I wasn't ready last time," he said, and his teeth ground at the lie-by-omission. He hadn't been ready, that was true, but he couldn't tell Sherlock that his unpreparedness was not the reason he'd pulled away. "You surprised me. I want to be prepared." He tried to smile. I can't believe I'm going through with this. And yet he could. He knew himself. He knew he couldn't let this go until they both reached the finish line.

Sherlock relaxed, but his eyes watched John suspiciously. "So this is an experiment," he mused. His brow furrowed in concentration; John had known that emotions were the hardest thing for Sherlock to figure out, but he had slightly overestimated his quickness. He simply nodded and waited. Sherlock flushed with colour, just a tint of pink, before moving in. He rested each palm on John's cheeks, and John felt his fingers softly touching his hair. John tried not to look away as he came closer, leaning in, careful and quiet this time. This was no adrenaline rush, John realized. He'd tried to convince himself that Sherlock had just been overexcited by the chase (and it had been a spectacular one; rooftop jumping, bus dodging, and an actual banana peel had all played key roles), but here he was, as calm as Sherlock could ever get, and John could see that Sherlock wanted this. For real.

Their lips met.

John tried. He really did. He closed his eyes, tried to pretend that Sherlock's lips were actually those of the woman at the clinic he'd had his eye on lately. Sherlock was holding back, perhaps for the first time John had ever seen, was hesitant about taking what he wanted. That was unusual. It was soft, tender, unendingly gentle. If the previous kiss had been an imperative, this one would have been a question.

This time, they both pulled away together, letting their eyes flutter open and find each other. Sherlock kept his hands on John's face, seeking an answer. John felt those eyes trying to see through him, and he looked up after a few moments. He knew Sherlock would see the answer in his eyes.

No. I'm so sorry.

He didn't have to say it. They'd gotten so good at communicating nonverbally that an exchanged look lasting three seconds spared them five minutes of spoken conversation. John cursed himself as he watched Sherlock figure it out; Sherlock closed his eyes, sagging just a little, exhaling slowly, trembling just enough for John to feel it. John hated to do it, but he brought his hands up and took Sherlock's wrists, lightly, and pulled them slowly away from his face, down, down, until his fingers slipped away naturally and they were no longer touching at all.

John hated that feeling of relief that flooded through him.

(He'd never been particularly physically affectionate. His family just Didn't Hug, Ever. His mates at school were forever clapping him on the back, punching his shoulders good-naturedly, and he took it with a smile, but he'd never returned the shoves. It just wasn't his style. He loved in his own way; he made tea, spoke comfortably in uncomfortable situations, made sure everyone around him was happy. He was never uncomfortable with his profession, which involved touching people for a living, basically; his approach was clinical, always cautious and careful and impersonal. Just as a doctor's touch should be. He wasn't specifically adverse to touching; the thought simply never occurred to him.)

"I'm going to go," John said quietly. He started to walk away, but Sherlock's hand reached out lightning fast, grabbing his forearm in a tight, panicked grip.

"Don't leave," Sherlock said. Please, his eyes said. I can't. I don't care if you don't want me. I just can't. Be alone anymore.

"I'm only going for a walk," John assured him. Sherlock relaxed his grip, and John gently tugged his arm away. "I'll be back."

And he did come back after two hours. But to Sherlock it seemed like days.

4.

John woke up screaming early the next morning. The dream had been unbearable; the searing sun blinded him to everything but the image of Sherlock, white as an angel, floating inches above the ground. Sherlock had lifted his hands to his own face, sliding his fingers gently down his cheeks, his neck, his bared chest, leaving a deep gashing trail wherever they touched, instantly seeping with much too much blood.

"John?"

He let one sob escape, and immediately Sherlock was kneeling by his bedside.

"You're home," he said firmly, reaching out cautiously to touch John's arm. John swatted the hand away and instead grabbed Sherlock around the neck, holding on for dear life as he tried to steady his breathing. This was the only time he felt comfortable hugging anyone; waking up after a bad nightmare, needing to feel for once that someone was really there, that real life was actually Real Life. He felt Sherlock's arms enfolding him in a comforting grasp, and he breathed in, deeply, sucking away Sherlock's warmth, taking what Sherlock gave.

And then he felt Sherlock's lips kiss his neck and almost cried again.

"I can't, Sherlock," he whispered. "Please, don't."

"Why not?" Sherlock asked, and the hurt and betrayal and rejection seeped through his normally steady voice. "You love me. You said it, once. Did you not?"

He had. There had been a dilapidated old building, and someone had placed a bomb inside while John had been inspecting the kitchen, and Sherlock figured it out in time and pulled John out himself and they'd just made it to the end of the street when it went up, the bang louder than anything John had ever heard. He'd laughed, breathless with escape, but Sherlock had been fierce, unwilling to let John go. "Don't ever scare me like that again," he'd hissed at him, one hand gripping each of John's shoulders too tightly.

John hadn't been able to make such a promise, so all he said was, "I love you, you know that?"

"Of course I know that," Sherlock had said, as though scorning the very possibility that he hadn't known something. John had nodded, satisfied, and let Sherlock hold onto him the whole walk home.

"Yes," John said, as patient as he can manage at three in the morning. "But there are so many different kinds of love. It's hard to explain."

"Do try."

John sighed, running a hand through his hair. How do you explain love to a person who has ostensibly never experienced such a thing? Sherlock shifted and sat down on the bed beside him, watching, curious.

"It's infinite," he started. "The differences in the way that people love. I can't possibly explain it all, ever. But listen. There's the kind of love where, say, I love jam. It's my favourite thing to put on toast. But if there ceased to be jam, I would only be disappointed. I wouldn't be distraught about it. Are you following so far?" Sherlock gave him a piercing glance and nodded once, sharply, indicating that John should continue. "Okay. So moving on. Think of it as exponential. The more one loves something, the more upset one would be if he were to lose that something." This was not going where he'd wanted it to go. He changed tracks. "Or you could think of it differently. For example, certain types of love are like this." John reaches over and took Sherlock's hand, clasping rather than weaving their fingers together. "Intimate, tight, squeezing, not wanting to lose hold of the other person. Other kinds are like this." He let go of Sherlock's hand but took it back almost immediately, this time a little more tender, and interlaced his blunt fingers with Sherlock's long thin ones. "Do you feel the difference?" he asked, hoping this worked. "I'm touching you in the in-between places, somewhere that few people ever touch. It's intimate as well, and tight and not wanting to let go, but in a completely other sort of way." He looked at Sherlock. "Please tell me this is making sense."

John loved this look on Sherlock's face. He'd seen it a hundred times, just before he spouted off the final deduction that would solve the case, and it never got old. Electricity and understanding seemed to spark off of him, illuminating everything around him, firecracker bright. "You love me like this," he said slowly, and John watched as he extracted his fingers and grasped John's hand again, clasped, fingers closed together, squeezing.

"Yes," John said, utterly relieved. "It's not the perfect simile, granted, but yes."

Sherlock nodded, slowly, still thinking. "I believe," he said, "that I can live with that."

John leaned over to hug him and whispered giddily, "You don't really have a choice, because I am not going anywhere."

"Ever?"

"Ever."

5.

That was a lie.

And now John is bleeding out in a cold, dirty alley somewhere in Brixton, Sherlock having run off ahead, forgetting that John would be slower for the sprained ankle he'd managed a few days ago. John didn't mind, of course; he let himself rest when he needed to, leaning against the brick wall covered in layers and layers of spray paint. And he'd forgotten that Sherlock had said, twenty-one hours before, that the murderer had a partner. As the bullet enters into the skin of his chest, ripping through layers and layers of flesh and bone and muscle, all John can think is I lied to him, I lied, I lied and he'll never ever forgive me.

"John, where did you—" John can still see, though his vision's gone a bit blurry, and what he sees breaks his heart over and over again. He sees Sherlock stop, frozen, as he figures out what happened, sees his whole body snap as though shot out of a slingshot, running toward the spot where John has slumped to the ground, now in a sitting position against the wall. He slides to the ground beside John, his breath coming in short gasps, his mobile phone out and dialing 999 already, and immediately places his hands over John's chest where the blood seeps out. He gives the directions and hangs up.

"I'm sorry," John manages to say.

"What for?" Sherlock mumbles, clearly too focused on keeping John alive to realize that he's already dead, was dead from the moment the murderer's partner took aim. He presses harder, hurting John, but the pressure brings him back for just a second and everything is clear and sharp and defined, nothing more so than Sherlock's face.

"I said I wasn't going anywhere," he says, his voice croaking but perfectly understandable. He knows Sherlock heard him, even though John is being resolutely ignored. "I didn't mean to. I tried to stay. I did my best."

He starts to fade again, his head lolling to the side, and Sherlock slaps him, hard, smearing John's face with his own blood. "Don't you dare," Sherlock warns him, but there's a tremor in his voice, like somewhere he knows, just as John knows, that this time one of them won't make it.

"I couldn't help it, Sherlock," John continues, murmuring now, slurring a little. "Please forgive me."

Sherlock dissolves instantly, like salt in water. He can only nod helplessly and hope that John can see him. He's crying harder than he's ever cried in his life, and it hurts, oh God don't leave me please you promised you promised I'll do anything I'll stop the experiments and I'll eat whenever you tell me to and I'll do the dishes please don't John don't John don't

And then he is bending over John's limp, dying form and Sherlock kisses him, hard, desperate, not asking this time but begging, senselessly, and he is shaking so hard and some of his tears hit John's face and slide down, making tracks in the blood. And John kisses him back this time, and Sherlock understands the message instinctively, John's answer:

I can't stay this time and I am so sorry but I love you.

"I love you too," Sherlock says after he breaks the kiss; the words come out broken, in choking pieces; he doesn't care as long as John hears him. John's eyes are closed, his face is ghostly white against the smeared blood, his body is still and his heart is beating its last few beats. But he smiles.