Author's Note: This is unfortunately the last chapter, my dears. I've had a lot, a lot of fun writing this fic, and your support and lovely comments have been above and beyond what I ever expected. I'm going to miss you all, but I guarantee you I will write more for this fandom, so look for my work!

I've actually got my next premise all picked out, so you lot will be the first to hear it: the five times Sherlock was in a box and the one time John crawled in after him. I know it sounds odd, but it popped into my head one day and refused to go away.

Warning: This chapter is pretty much straight smut and fluff. Smutty fluff sexy fluff-smut, though there's a dash of philosophy and some serious feels on the side.

Oh, and creepy-fun fact: a lot of the feelings I put in this are what I feel for my best friend, Teal, for whom I wrote this fic. It's said that the best writing stems from personal experience, and I've always tried to implement that. This is why I will never stop being a herald for the fact that Sherlock and John are the most incredible fictional friends that ever existed. This is in dedication to anyone who has ever loved someone completely, whether it was platonic or not.

…

…

By the time Lestrade and the rest of the police force caught up with them, Moriarty had vanished. Though the officers made a valiant attempt to follow his trail, Sherlock knew it was pointless. The master criminal was only ever found when he wanted to be, and this time it seemed he intended to disappear forever. Or at least until he reemerged to murder them all.

The world's only consulting detective had missed his final chance to defeat his greatest opponent. He'd lost. It was all over now.

And he didn't give one bloody fuck about it.

John was warm and strong against his side, his arms wrapped firmly around Sherlock's waist despite the fact that many of Scotland Yard's finest were openly staring at them. They were still lying in a heap of limbs on the ground, having failed to summon the desire to stand even though it had been half an hour since they'd fallen there together. The ruined death trap had been marked off with yellow caution tape, and dozens of people were scurrying around them with evidence bags like ants in an upturned hill. Nothing, however, could compel them to loosen their grips on each other, not Lestrade demanding they file a report, Anderson's smug remarks or even the futile efforts of the paramedics to put shock blankets around their shoulders.

Sometimes they spoke, little murmurs under their breath that only they could hear. Sometimes they gazed at each other, their eyes deep and whirling. For the most part, however, they were just holding each other, appreciating the warmth and life sitting next to them, the human being who meant so much more than flesh and bone. Nagging voices in the backs of their minds kept asking them what their lives would have been like if it weren't for that fateful day when two disparate individuals happened to need a flatmate, but they muffled them quickly. It was unthinkable. Gravity had brought them together, and that particular force of nature would not be defied.

The cab ride home was a single blip on Time's radar. Before they knew it, they were standing just within the door of 221B Baker Street without entirely knowing how or when they'd arrived. Two sets of feet trudged up the same staircase they'd climbed a hundred times before and walked into the same living room, yet everything looked foreign. Their eyes had been fundamentally altered to perceive the flat for what it really was: their life together. Their sofa, their piles of case folders, their scattered newspapers and half-drunk cups of tea. The flat wasn't a collection of furniture and personal possessions anymore; it was a map of the time they'd spent together, twisting and winding around them both until it curved off into infinity. It was every lingering glance when they thought the other man wasn't looking and every row over eyeballs in the crisper. It was the ever-present knowledge that their relationship was slowly changing them both, and it was all the time they'd wasted pretending they didn't realise it.

John took Sherlock by the hand, wrapping his firm, tan fingers around the other man's long, pale ones, and slowly tugged him towards the bedroom they now shared. There was one thing that had yet to happen between them, one urge they'd both hesitated to act upon because somehow it would make all of this real. Dreams, as flighty and fleeting as they were by nature, were intangible, which meant they could never be shattered. To make it real would mean to risk that one day it could fall apart, as all physical things eventually did.

Sherlock was ready for this to be real, though. He was ready to peel away the flesh above his heart, tenderly remove it from his chest, and place it in the care of another. It was unthinkable, handing something so fragile and soft over to someone else, but somehow it exhilarated him. He'd wasted so many years warring within himself, warring against the humanity he refused to acknowledge yet couldn't fully extinguish. When John had entered his life, it had been like a small leak had sprung in a blocked stream inside of him. As their friendship grew, more and more of it started to break through and trickle into his veins. Now, as John looked at him with love and wonder in his eyes, he could feel something bursting inside of him, flowing uninterrupted from the crown of his head to the tips of his toes. It was warm, and it reverberated pleasantly in his chest like the vibration of violin strings. He'd been so lost and so afraid of his own thoughts, but now he could finally be at peace with himself. Someone loved him. Someone understood him. He didn't have to be alone ever again, and for the first time in his life, he didn't want to be.

They fell together onto their bed. Their hands moved unhurriedly over each other's bodies, exploring and touching and tugging clothing open. They both felt the heat simmering just beneath their skin, but they moved slowly, reveling in every detail of each other's bodies as they were slowly revealed.

Sherlock decided that John had the most perfect skin in existence. His entire life story was scrawled across it in a language only a lover could decipher. The collection of scars and freckles told a tale, and the detective took great care in running his mouth over each and every one. He lingered over the bullet wound in John's shoulder, dipping his tongue into the small hole of knotted flesh that would never fully mend. This was the wound that had sent John to him. This was the end result of an act of hatred that had changed their lives fantastically. He had never been one for bouts of optimism, but he allowed himself to think for one fleeting moment that the worst of human atrocities could breed wonders in their wake.

John was quivering beneath him as he reverently examined the story written on his flesh. His calloused hands—flecked with innumerable scars—spoke volumes of his time as a doctor and a soldier, a healer and a killer. Laughter and sorrow were etched into the lines around his eyes and lips. His burdens were carried in the bags beneath his eyes. His sandy hair and the unusual shade of his dark blue eyes were the work of ancestors he would never meet. Every strand of hair and corded muscle combined to form the body of John Watson, and they whispered a sad and beautiful history into Sherlock's ears.

John was touching him now, and he bit his bottom lip hard to keep from moaning obscenely. The tingling inside his chest was growing stronger, spreading into the tips of his fingers and feeling like light and velvet. He had never been more turned on in his life, but he couldn't restrain his desire to look at every inch of his lover until he had him memorized. He wanted to count his eyelashes and make a stone rubbing of his ribs.

John had neither Sherlock's patience nor his penchant for cataloguing minute details. Before the detective could so much as exhale, he found himself on his back, pressed into the mattress as a flushed and golden John Watson crawled on top of him. His innards shivered and leapt into his throat at the sight, and a spike of hot desire rushed through him only to pool low in his abdomen. John's eyes were dancing over him, mapping his body in much the same way Sherlock had done to him moments before. They had become constellations that only the other man could decipher.

"You're magnificent," the doctor whispered before leaning down to claim his lover's lips with his own.

The kiss started out gentle but quickly grew urgent as the taste of each other coated their tongues. Their bodies moved hungrily together, touching and rubbing in a futile attempt to satiate their need. This was different from the other times they'd come together, wrung moans from each other's throats and eagerly drunk them down. This was infinitely more intimate and had lifetimes of adoring intent behind it. This was what John had been talking about what seemed like ages ago. This was about them, pleasing and loving each other on a deeper level than merely catering to their bodies' needs. Sex may have been a matter of biology, but this was a matter of chemistry.

When John's hand wrapped firmly around his prick, Sherlock hissed and arched his back until the cartilage audibly popped. Desire—hot and dark and primal—overloaded the circuitry in his brilliant mind and made the edges of his vision crackle. He shoved a hand between their bodies and fumbled for John's erection, eager to return the favour before he lost all ability to form coherent thoughts. He heard John exhale breathily and felt his cock twitch in response. Never had another individual's respiratory patterns thrilled him so completely. He stroked him in long, languid pumps, drawing out his pleasure until he both felt and heard him shudder. Their sensations were linked, dependent on not only what they were feeling but what the other was feeling as well. Sherlock experienced each and every one John's moans as if they were his own. He fed on them like fire licking at the edges of an endless source of fuel. The inferno mounted higher and higher until he knew the dénouement waiting for them was going to be akin to a localised Apocalypse.

It wasn't enough to simply touch each other. Sherlock felt an ache deep within his body that was snarling at him, demanding to be fed. He was hollow inside, and John was the only being in the history of existence that could fill him. This went beyond physical need and into the realm of spiritual epiphany. John was a piece of himself—something like a soul, the kind that he'd heard religions digress endlessly about—and without it he would burst into a thousand smoldering pieces.

John knew it too. Sherlock could see it in the feverish gleam in his eyes and the way he simply could not stop trembling. The doctor looked helplessly at him, and in an instant he understood. He reached over to his nightstand and pawed at the drawer, only partially able to function while this much raw need was pulsing through his body. He'd known this moment would come and had prepared accordingly. From his bedside table he produced a bottle of lubrication and shoved it impatiently into John's hand. He'd also purchased condoms, but to his delight John had "secretly" been tested for any STDs shortly before the first time any fluids had been exchanged between them. Sherlock had found the paperwork in his sock drawer, all of which joyously declared that John was as clean as could be. He himself was routinely tested due to his past struggles with addiction and the amount of time he spent handling blood and other biological samples. Even in a laboratory setting, one could never be too careful. They were free to join their bodies together without the slightest trepidation.

"Sherlock," John murmured as he opened the bottle and poured a generous amount of lube on his right index finger. "I need you so badly."

The detective responded by spreading his legs wider, gasping quietly when he saw the quiver that ran through his lover in response to that small action. John reached carefully down between them and prodded at Sherlock's entrance, smearing a layer of lubricant around the ring of muscle. He pushed slowly in, biting his lip to suppress the moan Sherlock could hear simply by looking at the way his neck tendons were sticking out. The detective watched his lover's face as his body was invaded and could feel what John was thinking. He wanted so desperately to bury himself in him but refused to hurt him. The mild pain and burning sensations were forgotten in lieu of admiring this inner dialogue.

Only when the head of John's prick was pressed to his entrance did the reality of it finally set in. They were going to feel each other inside and out, and it was going to be so much more than either of them ever thought they could expect from life.

John pushed into him, and Sherlock experienced every inch as the splitting of his consciousness. His brain was floating in a sea of hormones and dopamine, and his thoughts were swathed in gauze. His body was floundering in too many sensations for it to categorise. He was burning and writhing and howling, and he had absolutely no control over this helpless shell of flesh that was gripping onto John's shoulders for dear life. He felt his lover sink himself to the root inside of him, and in one blinding moment of white, everything that he was knit itself together with everything that was John.

The doctor made a keening sound and shivered so violently, his whole body vibrated. Then he rocked his hips experimentally inside of him, and they both groaned together. The sensation Sherlock felt in that moment was betrayed by the confines of the English language. It was perfection and undulation and cosmos and microbe and everything and nothing all rolled into one impossibility that made him dizzy at the thought of assigning a word to it. No amount of alphabetic sawdust could contain the breadth and depth of this culmination of every decision he had ever made in life. This was himself as a link in an unfathomable chain reaction, and he never wanted it to end.

John took a few trembling thrusts into him, gasping for the breath that refused to stay in his lungs. Sherlock clawed at him weakly before wrapping his boneless limbs around him and opening himself entirely to the savage ecstasy that was being enacted upon him. He felt every thrust as a biological drive, as necessary to him as breathing. He wondered how he'd ever survived without John inside him. He needed this. He needed this pounding heart and this electric tingle running down his spine and this pleasure, burning hot, deep inside of him.

It was like looking up at a wall of blue sky and thinking that was as far as space went only to have night fall, the sky turn transparent and the entire galaxy unfurl itself before him in endless stretches of ink and diamond.

His voice joined John's as they moaned together harmoniously. Their skin was slicked with sweat and made them slippery as they moved, their hips rolling in an effortless rhythm and their hands mapping the flesh that dared to contain them. Sherlock felt a coil tightening deep in his stomach and knew he wasn't long for this world. John's thrusts were growing frantic and frenetic, and the ragged quality to his moans denoted his distress at the raw sensation coursing through his veins. It was so good it burned and raked at his insides, rendering them into ribbons of feeling.

Half a dozen cosmos-shattering thrusts later, they were both screaming and unravelling. Sherlock felt himself implode, condense and then burst into flames. He twisted beneath the force of an orgasm so powerful it flirted with the line between ecstasy and agony. It was the combination of all five of his senses at once, and they were each competing for dominance. He could do nothing to contain himself as he wordlessly howled the profoundness of the contractions wracking his body and leaving pulp in their wake.

When his mind awoke and his body regained its sentience, he was panting beneath a limp, sweaty John, and both of them were gasping for breath that simply refused to come.

The doctor shakily removed himself from the detective's body, and Sherlock felt the loss like a blow to his consciousness. John rolled onto his side and drew up to him, wrapping his limbs around him and then deflating with a ragged breath that signified both exhaustion and saturation.

Words hung in the air between their bodies but never solidified enough to be spoken.

Sherlock took long draughts of breath, feeling the expansion and compression of his chest in a whole new way. John's eyes were half-lidded and glazed next to him, too close to be in focus, yet the hint of delirium in them was obvious.

In the last moments before he knew John would slip into deep sleep, Sherlock murmured words he'd never once before spoken aloud.

"I love you."

John half-started before settling back into his easy, wrapped-around-Sherlock posture.

"I love you more than words can say."

They both fell into the soundest sleep human beings are capable of having.

…

…

John clutched at his temples and struggled to rein in his temper.

"Sherlock, you can't spill hydrochloric acid on the kitchen counter and then just throw a towel over it."

"Why not? It's not as if the wood is going to regenerate itself. We should simply avoid the spot from now on."

John counted to ten and then took a deep breath. For being so brilliant, Sherlock lived up to the phrase John had assigned to him within days of their first meeting: spectacularly ignorant.

"You could at least warn me that it's there."

"I assumed you would notice when you saw the towel smoldering."

John bit his lip and sucked in a breath. He couldn't help but feel that he'd saddled himself with a very large child for the rest of his life.

At the same time, sunlight was streaming through the kitchen window and catching Sherlock's cheekbones at just the right angle to make him look like sculpted marble. The detective either didn't know how flawlessly beautiful he was or didn't care enough to comment on it. Either way, he needed to learn to stop being so dazzling, or else John was never going to be able to focus again.

The doctor felt his anger melting away as he looked upon a face that, for all its beauty, could not begin to capture what lay beneath it.

"You're an absolute dick, but I suppose I love you anyway."

Sherlock smiled—really smiled—and place a pale hand on his cheek.

"I can't thank you enough for that."

…

…

They were getting older.

Sherlock, for all of his deductions and infinite understanding, knew it but could do nothing to stop it.

It manifested in the new lines crinkling around his eyes and the gray hairs that sprinkled John's temple. They were still racing across London, hot on the heels of this criminal or the other, but Sherlock could feel in his bones the first whispered hint that it could not last forever. One day, they would be too slow, too fragile, to leap across rooftops with their coats flying around them like dark wings.

Sherlock was astounded by how pleased the idea made him.

He had spent years dreading the inevitable corrosion of his mental and physical faculties. The work had been his entire life for decades, and the idea of losing the only thing that mattered to him was abhorrent. Things had changed, however, as he spent more years in the company of Dr John Watson. He still aided the police when they were out of their depth, as was always the case, but it was no longer the sun at the centre of his galaxy.

He had a new purpose now, a new goal for the remainder of his life, that didn't involve solving murders or toppling crime rings or proving to the world that he was clever.

His greatest aspiration in life was to love the man who stood unfailing by his side and to keep earning his love in return.

He would never tire of hearing John tell him he was brilliant when he pointed out what was obvious to only him. He would never tire of returning to 221B Baker Street at the end of a long day and seeing John sat in his chair with the newspaper as always. He would never tire of falling asleep at night wrapped in the arms of the only person who was never tedious or dull.

His life had rocketed off onto a completely unforeseen trajectory—a glitch in the laws of physics that he'd discovered by accident—and he was thankful every day that it had.

…

…

In an astounding moment of humanity, John realised that he was going to die.

He'd known it since he was a child, of course, but knowing and understanding—really grasping the notion—are entirely separate entities.

One day, his heart would stop beating. He would feel it stutter in his chest, would panic as he waited for it to beat again, and then he would know, as the breath seeped out of his lungs, that it would never pulse again.

It would be the most intimate moment of his life, something that only he could experience in his own private, quiet way, and there would be no one but himself to help him through it.

It was more frightening than any other realisation he'd ever had, yet he understood the futility of fretting about it. It was irrefutable fact. There was no sense in being afraid of it.

But he was.

He was terrified.

The depth and breadth of the unknown were waiting for him to leap into them, and there was no telling how far into the abyss he might fall.

His real terror, however, stemmed from the knowledge of what he had to lose.

He'd met the proverbial love of his life, the most incredible, incomprehensible human being that had ever existed, and he'd been fortunate enough to win his love in return.

One day, he would leave Sherlock. Or Sherlock would leave him. Even though they'd shared everything they had with each other, they could not share this.

One of them would have to continue existing without the other, continue living on an Earth that no longer contained oxygen or sunlight or gravity.

It was the most bone-chillingly terrifying thought he'd ever had, but it birthed sympathy in its wake.

There were people who'd never had this feeling. There were people who'd never found someone they loved so much it frightened them. There were people who'd had the chance to feel this but were too insecure or too afraid of their own vulnerability to accept it, and so they chased it away. There were people that wouldn't comprehend these fears if he tried to explain them.

He had almost been that person.

He'd been so alone, so plagued by the war and the unspeakable things that he'd done, that he'd almost let himself be swept away in the suffocating tide of it.

He understood it now. He understood the jealous lovers that murdered the mistress and the people who gave up incredible jobs so they wouldn't have to move away from their families and the old men and women who seemed to wither away and rot when their spouse died before they did. It was a symbiotic relationship that bordered on parasitic. Love was the disease and the cure that never stopped feeding on itself and never ceased to be indescribably beautiful.

With the shift of a few grains of sand—so small and insignificant that John had hardly noticed their passing—his life had become something entirely different. Then the whole hourglass had tipped itself over, and now Sherlock and he were eons away from what might have been.

All lives end. All hearts are broken.

The best-case scenario is finding someone more precious than you could ever be, loving them for a lifetime, and then either losing them or leaving them to try to piece themselves together after you're gone. That is the dream that most people seek without ever understanding the ache and undoing they're about to bring upon themselves.

John loved Sherlock with every atom of every sinew in his weak, fleshy body, and he couldn't help but think that even after he died, all of that feeling had to go somewhere. Maybe it would rush out of him in a cloud of sparks and lightning, or maybe it would shoot down into the ground until it reached the Earth's core, or maybe it would burst up into the Earth's atmosphere, pass through it and join the scintillating stars.

Maybe it would do nothing and mean nothing in the end of it all.

But it was there. Living inside of him right now.

So long as his heart was beating in his chest, it was alive, and so was he.

And then Sherlock was by his side, grabbing his hand and dragging him off towards some new adventure.

John gripped onto him so tightly that the other man began to complain. But he didn't let go.

He never stopped holding onto him. He couldn't if he tried.

…

…

Sherlock was beginning to understand why so many people believed in God.

Of all the life paths he could have chosen, the glaring majority of them had led to him solving crimes, living alone and being an "annoying dick", as John had once so eloquently phrased it.

He hadn't ended up with the life he'd thought he'd have. He'd offered himself to another person, and that person had whole-heartedly accepted him, despite a plethora of logical reasons that should have chased him away. People could cheat or get divorced or decide their differences were irreconcilable, but that was not one of the paths available to him. Sherlock was going to spend his life with one idiotic, adorable, daft, and utterly flawless man, and nothing could ever change that. They were each other's final problem and final solution. The end and beginning of all there was had started with a single day in St Bartholomew's laboratory, a microscope, a mobile phone, and not the slightest inkling that an undiscovered force of nature had just been set into motion.

But it would end some day, as all great things inevitably did.

It made perfect sense, in Sherlock's mind, for John and him to continue to be with each other forever. Perishable human bodies, however, dictated to the contrary.

He'd never been a man of God. God didn't matter. He didn't make the world turn the other way round or stop killers from pulling the trigger, and so He did not matter.

In a sense, however, Sherlock had begun to understand His draw.

When his body finally gave way and when John's did the same - in whatever order they chose to do so - life would cease to be logical. No matter how many years they had initially spent apart, their final joining had been the perfect answer to the most unthinkable problem. They were meant to be one. They were a scale that was so perfectly balanced, the weight of the world could not undo it.

Sherlock, despite every urging of logic and rationale, couldn't help but hope, deep in his heart, that they would always exist, that there would never be an end to it. They would come together again, and even though it defied the scientific world he loved—the world he could touch and quantify and verify with his own two eyes—he hoped, deeply and thoroughly, that there was an eternity of John somewhere out there for him to delight in.

He hoped—no, he prayed—for the first time in his life, that he was wrong. He prayed there was more than what his brain, for all the things it saw that others missed, could understand.

He prayed that not even death could separate a pair as perfect as Sherlock Holmes and Dr John Watson.

…

…

The End.

…

…

Author's Note: I usually hate to put closing notes on things because I feel it kills the mood, but fuck it. I'm more proud of this than I've ever been of anything I've written in the past. I love Sherlock and John so much that they compel me to put words on paper that hurt me but make me so happy.

I'd like to give one final shout-out to Devin and Alex of fuckyeahjohnlockfanfic . tumblr for recommending this story so much and generally being loves. I am again so honoured for the recognition, since I know you read massive piles of wonderful fan fics. You ladies are truly a blessing on this fandom. If anyone out there is not following their blog, you're missing out.

I loved this. I loved doing this. I loved getting into Moriarty's head and swimming around in there. I loved writing about a silly scheme that turned into real feelings and then turned into this final chapter. I loved hearing from all of you.

I hope you guys enjoyed this even a fraction of how much I did. If you did at all, please please please send me your thoughts. I need to talk to someone about this thing that I did.

I will be back. Look for me.