Sherlock paced Mycroft's obnoxiously posh flat as he worked his way through his third cigarette. It had taken two before his hands stopped shaking. He didn't bother opening the window. Mycroft was a prat; he deserved whatever smoke fumes he got.

He circled the grand piano as he made his way from the living room to Mycroft's office and back again. Of course Mycroft's flat was large enough to contain a grand piano (Sherlock hadn't heard him play in a long time, but under duress he would admit that his brother had more talent than even the most revered of the modern pianists, though he never played in public. It was their mother's greatest joy when she could guilt trip the two of them into playing together, and they made sure to do it as seldom as possible.)

Sherlock arrived in the kitchen only to turn back around for the living room. Mycroft was not home. Sherlock had known he wouldn't be. He rarely used this flat. When he wasn't out of town on business he preferred to use the rooms he had in the centre, closer to his office. Breaking in hadn't exactly been easy, but then Sherlock did not require easy when it came to breaking and entering. He never let Lestrade forget how fortunate it was for Scotland Yard that he found solving crimes more interesting than committing them.

He raked his hand through his hair, sensory memories of John's hands hot on his skin. The look in his eyes, the low growl of his voice— Sherlock took a long drag, letting the smoke burn the taste of him from his mouth. God, what had he done?

He'd been so certain when he kissed John that he could handle it. But he had underestimated by far the strength of John's reaction and the strength of his own. He'd thought he could tolerate the damage, withstand the impact. But upon being confronted with the reality of the destruction—the perfect organisation of his mind palace upended by the chaos of emotion—he couldn't let it happen.

John was the most important thing in the world to him. But his work, his mind palace, was him. 'Sherlock Holmes' was only a synonym for 'consulting detective.' If he allowed emotion to flood his mind palace, he wouldn't be who he was. It had taken him nine days to notice John was poisoned because he had been distracted trying to hold back waterfalls of feelings that were threatening all the time to sweep away his identity, leave him with nothing but a headful of emotional need and sexual want. He had an addictive personality. He knew this. If he allowed himself to want John… It was doubtless the addiction would follow swift and all-consuming.

Once upon a time it had been easy. Excepting any time John was in real danger, the Closet had been enough keep the cluttering feelings clear of his consciousness. He had deluded himself so well that the searing pain of saying goodbye to John (as he stood on the rooftop of Barts) had almost come as a surprise—tears springing to his eyes at the unexpected sensation of being torn in half. Since when had John become such a significant part of him that leaving the doctor behind resulted in the detective going forward incomplete? A gaping hollow left cold where something warm had been.

The emotions surrounding John in his mind had only become harder to contend with after that. He had thought perhaps things would stabilise after John's wedding. But then John left Mary and came back to Baker Street and it was everything Sherlock had wanted until that night in the cemetery when he'd realised it wasn't. It wasn't enough.

Sherlock pressed his palms into his eyes. He couldn't hold back the floods anymore. He didn't want to. He'd thought he would simply let go and deal with the consequences accordingly. He had been naïve. But how could he have known the full extent of the repercussions? He'd suffered through the disagreeable act of kissing in the past; he'd never experienced anything like what had happened in the kitchen today.

His wrist trembled as he held the cigarette to his lips, remembering the scrape of John's teeth against them—of John's tongue against his own… It was only kissing. What state would he be in now if John had— Sherlock shut his eyes in attempt to stop the thought in its tracks. He remembered the tenderness of the kisses on his face. He wondered if John had kissed any of his past partners like that. He felt a wave of nausea that had nothing to with the dousing of nicotine his body was taking.

He checked his phone: nothing from John. Sherlock hadn't sent him a message either. There was nothing he could say. At least not until he solved the problem. There had to be a way he could have what he wanted—give John what he wanted—without compromising his mind palace. Why did desire have to be such massive mental real estate? How could he find space for it when his brain was already filled to critical levels with essential information?

It was true some part of him wanted to give up and give over all the space he had in his mind to John. That, perhaps, had been the part of him responsible for the decision to kiss his doctor so recklessly today. But a stronger part of him knew that if he let go of his mind palace he would lose himself, which meant losing everything John admired about him. A Catch-22. But there must be a solution. He had to be able to reason his way out.

Sherlock took a fourth cigarette from the pack. They were good for brainwork. They were going to help him find a solution that would allow him to have what he wanted. There were so few things he wanted, and with cigarettes, cocaine, and heroin off the table, he needed something on the table. Preferably an army doctor, preferably shirtless— Sherlock fumbled trying to light the cigarette in his hand.

Late the next night found Sherlock turning Mycroft's flat upside-down looking for cigarettes. He knew his brother. Mycroft didn't smoke often but Sherlock knew he kept some on hand for the occasional period of stress or even as an alternative to eating (Sherlock was quite complacent in his knowledge of his brother's stress-eating habit that caused him to go up and down suit sizes depending on the state of political affairs). He swore under his breath as there turned out not to be cigarettes anywhere in Mycroft's office, not even in the hidden compartments of his desk.

He moved to the living room, targeting the bookshelf. He scrutinised it carefully, reading the dust on the shelves. Mycroft owned an e-reader; he wouldn't have had cause to take one of these books down recently. He just needed to find—there it was: a break in the thin layer of dust. The book had been removed and replaced recently. It was leather-bound, one of many in a set of classics. Sherlock looked at the title: Emma, by Jane Austen. If he had ever known who Jane Austen was he must have deleted it. But unless Emma was a dictator in an oil-rich country he supposed his brother wouldn't have any interest in the material.

Sure enough, opening the cover revealed a large, rectangular hole cut out from the centre of the pages, leaving only the margins intact. How very Victorian, he scoffed at Mycroft, plucking out the pack of cigarettes. There was an envelope folded behind it. When Sherlock turned it over he was faintly surprised to find his name written there. (He supposed it was just as well considering he would have opened it anyway.)

The envelope contained a note in his brother's handwriting. It read:

Bookcases before bureaus, brother dearest. I believe you'll find an answer to your problem in the enclosed text. Enjoy the cigarettes. I bought them low-tar especially for you. M

Sherlock stared at the page in amazement. His endlessly infuriating older brother had anticipated everything. He had been at the hospital. He'd known. He'd seen exactly how it would play out with John, right up to Sherlock being here, looking for cigarettes, and searching his desk before the bookcase. It was only at the times when he was forced to interact with Mycroft that Sherlock got just the smallest glimpse of why ordinary people hated him so vehemently.

Sherlock drew the second sheet of paper from the envelope and balked. It was a page torn out of a book. Eighteen lines of text. It was a poem.

He blinked in disbelief. Mycroft had known he would come here in a crisis, and he'd left him low-tar cigarettes and a poem.

Sherlock wondered if he could put enough pressure on the right people to get Mycroft transferred to Siberia.

Five hours and half a pack of low-tar cigarettes later Sherlock discovered with finality that the poem was not a cypher. He had employed every method of cryptography he knew and yet it would not break. He was forced to face the inevitable conclusion: the poem was only a poem.

Sherlock despised poetry. Riddles were one thing—they were based in logic. Poetry had nothing to do with logic. It was nothing more than a mess of emotional vomit—sticky and noxious with its unbridled excesses: whining, pathetic sorrow; syrupy, sickening love; idiotic, babbling joy. Nothing he could work with. Of course Mycroft would have known that. A puzzle he couldn't solve.

He crumpled the poem and tossed it to the floor. He didn't need his infernal brother's help.

It wasn't until the next night that he picked it up again, uncrumpling the paper a bit more forcefully than was necessary.

He dropped down onto Mycroft's couch and lay back. He'd analysed the poem from every angle he knew with no result, and he'd made no other progress to speak of. But this wasn't a matter that concerned only him. It was about him and John. And perhaps, he thought as he closed his eyes, it was time to ask for John's help.

Wearing a black pair of wellies Sherlock stepped carefully through the disaster zone that was his mind palace. There was rubble from the walls and ceilings, books, papers, and boards strewn throughout the area. Water was still rushing over the floors, through the level had lowered enough now to just reach his ankles. He made his way to John's door, which was hanging off its hinge.

John was sitting on the edge of his bed, facing the door as though he'd been waiting for him. He was also wearing wellies, absently splashing the river flowing across the floor with one foot.

John looked up, giving him a small smile.

Sherlock hesitated in the doorway. He knew it wasn't really John. It was only his mind's image. But still he hadn't seen him since—since the episode in the kitchen and he found even an incorporeal John caused his throat to tighten, making it difficult to swallow.

"Bit of a mess in here," John commented, looking around with an amused expression.

"I'm trying to fix it," Sherlock said, walking further into the room.

"How's that going?"

Sherlock shot him a glare and John licked his lips—a longstanding habit of the doctor's, but Sherlock had never remembered it being so distracting.

He refocused. "Take a look at this," he said, pulling the page he'd memorised from his pocket. He handed it to John. "Mycroft says there's an answer here."

John stood up from the bed and took the paper. "It's a poem," he said with some surprise.

"A sound analysis, John, but I was hoping you'd go deeper."

John's eyes flashed up at him in annoyance, but he returned his attention to the text. Sherlock waited. John was a writer. Perhaps he could make something of it. Well, he wasn't a writer so much as a blogger. How did bloggers fair with poetry? Sherlock didn't know.

John smiled a bit as he read.

"Well? What does it say?"

John looked up. "Can't you read it?"

Sherlock sniffed. "No. I'm not versed in emotional drivel."

John glanced over the words one more time. "It says you're human. It says you're allowed to love." He shrugged, refolded the paper, and handed it back to Sherlock.

Sherlock furrowed his eyebrows in disdain. "What kind of message is that? I don't need permission from Mycroft for anything, let alone— Especially—" Sherlock began pacing the room, boots splashing in the water. "He's one to talk," he scoffed. "He's the one who—he told me—" He broke off, scowling indignantly at the ground.

John was watching him pace. "He told you you weren't allowed to love."

Sherlock snapped his head up. John was gazing at him steadily—irises flecked in shades of blue… This exchange might have been easier if he had imagined John with a bag over his head.

He considered John's words. Mycroft had never said it in those terms, but as a nine-year-old boy wasn't that exactly how he'd interpreted it? Really it didn't matter. Even as a child Sherlock had never blindly accepted a rule, not even one from Mycroft. He did his own research; he evaluated evidence on his own terms. Redbeard's death had lent credence to his brother's words, and with time he had come to see the soundness of the logic for himself. Sherlock had spent most of his childhood learning, rather bitterly, that Mycroft was usually right. And he wasn't wrong about this either: Love is only weakness.

The reasoning was elementary. Even if Mycroft had never said anything, Sherlock would have come to the same conclusion. He didn't like people and they didn't like him. As he grew up it was clear there was no one worth his time, let alone any kind of risky emotional investment. It was obvious. He hadn't needed Mycroft to tell him that. He would have put the pieces together on his own.

So the question now was what—

"What is this supposed to mean then?" Sherlock demanded incredulously, brandishing the poem at John. "Has he changed his mind? Is he telling me he was wrong?"

"Oh, Sherlock, you're a very stupid little boy."

Sherlock whirled around and found Mycroft standing in the doorway sporting a similar pair of black wellies.

"Of course I haven't changed my mind," he said, walking to stand directly in front of Sherlock. "And of course I'm not wrong." He raised his chin, using his extra two centimetres to his advantage. Sherlock got his own back by giving Mycroft a rubber duck pattern on his boots. It was still his mind palace, after all.

"The poem seems to suggest otherwise," Sherlock countered coolly. "Exceptions to your infallible logic, dear brother?"

"I'm afraid that, as usual, you are entirely missing the point." The disappointment in Mycroft's tone was something Sherlock had learned to tune out from an early age. "The theory regards love as a vulgar distraction for an idle mind and a dangerous weakness for a powerful one. It is illogical to make oneself vulnerable in exchange for an arrangement that can only end in loss and pain."

"Yes, and?" Sherlock knew all of this already.

"The logic," Mycroft said sharply, "has nothing to do with pretending not to have fallen in love once one has already done so."

Sherlock's jaw clamped shut. Oh. He looked over at John, who was standing at ease, hands clasped behind his back, head down. Oh.

"You have been vulnerable since that night in Brixton, and your enemies know it. Surely you must understand that the logic evaporates if you are already in love. The point of the theory was to spare you pain. But it's too late for that. You've been through it already."

Sherlock hadn't taken his eyes off of John.

"And you'll go through it all again. It'll be much worse when he dies."

John was motionless, head down.

"You managed to avoid this kind of entanglement for a long time, but there's nothing you can do about it now. Your feelings tie you to him, regardless of whether you pretend it isn't so."

"I know," Sherlock said softly. Because he must have known. It wasn't Mycroft speaking.

"Always so logical, little brother. Where is the logic in pretending?"

"The emotion is too strong. It's too messy," Sherlock tossed the word out in frustration. "I can't think clearly with it in my head. He motioned to the space around them. Look what it's done!"

Mycroft sighed. "Sherlock, I can't even begin to tell you how little your plumbing problems interest me."

Sherlock gave him a rubber duck rain hat to match his wellies for that. He turned to leave.

"Mycroft—"

Mycroft stopped at the door and turned. "'Tell me about despair, yours, and I will tell you mine. Meanwhile the world goes on.' The world goes on, Sherlock."

He left.

Sherlock started when he found John standing directly at his side.

"It's not quite as moving when he says it with the ducky hat on, is it?" John mused.

"No," Sherlock muttered, distracted.

John put a hand on his shoulder and Sherlock turned toward him. "You can fix this," he said.

Sherlock huffed in frustration. "Every time you so much as touch me I get the Niagara Falls worth of feelings crashing through here. And I can't—I'm not strong enough to stop it. I tried." Sherlock looked away. He didn't like admitting failure, even if it was just to a figment of his own imagination.

John shrugged. "It's a design flaw."

Sherlock looked back at him.

"You're trying to stop it. Don't. Don't stop it. Control it. Incorporate it instead."

Sherlock stared at him. Incorporate it.

"If the current design isn't working, renovate. Remodel."

Sherlock's thoughts began to whir. John was right. He could redesign. If he could work his feelings for John into the very structure of his mind palace he could control them.

He knew what he needed to do.

"Are you ready?" John asked, taking a step closer.

"Yes."

Sherlock closed his eyes and John kissed him. Softly first, and then more insistently, memories of their previous kisses ghosting through the press of his lips and the slide of his tongue. The river running over their boots swelled up past their ankles. John tightened his grip on Sherlock's waist. "Focus," he whispered against his lips. And Sherlock did.

He gripped John's hips, feeling the narrow firmness of them at the band of his jeans. He ran his hands up under his jumper as he kissed him, fingers feeling the sturdy form underneath—a map of flesh and bone Sherlock had memorised long ago—the strength in his elastic muscles. The water was threatening to rise above mid-calf and Sherlock held the sides of John's face. He paused for a moment, just taking it in. John's face: so familiar and so pleasing, smooth planes of honey skin, several shades darker than Sherlock's, the mouth that smiled or tightened in accordance with his moods, lips that shouted reprimands at him or pressed firmly against his own. There was nothing he wanted more than John Watson.

Sherlock shut his eyes, tilted his head and caught John's lips, feeling the weight of his friend's body as he relaxed into him. Don't stop it. Control it.John wrapped his arms around Sherlock's waist as he kissed him back. Control. Sherlock felt the pressure of the water around his legs disappear. He could still hear the sound of rushing water but he didn't open his eyes. He carried on kissing John. He kissed him like there was nowhere else he would choose to be, and nothing else he cared to do more.

When John finally stepped back and Sherlock opened his eyes slowly, his mind palace was completely changed. The mess and rubble had cleared away, leaving the room as neat and pristine as it had ever been. But now the walls were glistening like fountains as streams flowed down from high ceilings, disappearing into the void beneath the floor. The sound had quieted when John stopped kissing him, and as John stepped away the amount of falling water diminished until there were only soft rivulets sweeping silently down the sides of the room.

"Very nice," John said, looking around. "Not a bad idea, hm?"

"Yes, John, you're much cleverer today than usual."

"Well, it's your brain," John replied tetchily.

Sherlock grinned. "True."

He stepped out into the corridor and found the walls there similarly altered. John followed as Sherlock walked through the palace, inspecting his new design. It had been accomplished flawlessly. The rooms were completely dry. The water cascaded harmlessly down the walls into depths below the floor. He couldn't believe he hadn't thought of this before. The reason his emotions for John had caused such chaos in his mind was because there was no space for them, and they were too powerful to be locked away.

The new design fully integrated his feelings for John throughout his entire mind palace. They took up no space at all, but at the same time they were omnipresent, surrounding his mind completely—insulating it the way John insulated him from the world. They were like John's presence at Baker Street: Unobtrusive and quiet, but so essential, so thoroughly woven throughout the space that it would be someplace else entirely without it; comforting, pleasant, always with him, in every room of 221B and now in every room of his mind palace.

He'd never had to worry about John inhibiting his ability to work, annoying him the way everyone else always did. It had never been like that with John. John was different. He alone enhanced Sherlock's thought process instead of deterring it; he made him better. And now it would be the same with his mind palace. He wouldn't shut his feelings for John out; they would transform the space; they would improve it. The silent falling water had a calming effect that would help Sherlock concentrate. It would make him better than ever. The way John had.

"Want to give it a test run?" John asked when they stopped in Sherlock's library, smile playing at his lips.

Sherlock stepped toward him. "If we must."

John angled his head to kiss him, but ducked at the last instant, bringing his lips to Sherlock's neck instead. The water poured down the walls, becoming audible as the amount increased. Sherlock's eyes fell shut as he felt the scrape of John's teeth and the dart of his tongue—a blissful alternation against his skin. Sherlock ran his fingers through light strands of hair, catching and pulling John's head back and kissing him properly, claiming his mouth in a way that wouldn't allow John to forget who it belonged to now. The waterfalls tumbled down the walls around them, picking up volume until they were roaring—a reminder of a time they'd stood together on the cliffs under the Reichenbach Falls, danger in the air around them like mist, but this was home.

When John pulled back and Sherlock opened his eyes, there was no damage. Not even stray splashes. The water lessened, dwindling back down to quiet streams, thin enough just to glisten along the walls as it caught the light from the palace windows. Sherlock turned, looking around the room as the realisation sank in. He had done it. The water his mind had chosen to represent his emotion for John was contained.

He spun around and grabbed John's upper arms roughly. "John, I did it. I solved it. This means we can— We can—"

Sherlock's eyes flew open. Daylight was flooding through the windows of Mycroft's flat. What time was it? He checked his phone: Two p.m. What day was it? Saturday. John would be at rugby practise. John. He had just enough time to get home, shower, and change clothes. He supposed John would be more inclined to kiss him if he didn't smell like cigarette smoke.

He leapt off the couch and the poem dropped to the floor. Sherlock would have left it there, but he hesitated, considering. He snatched the piece of paper up and jammed it into on his pocket on his way out the door.

You do not have to be good.

You do not have to walk on your knees

for a hundred miles through the desert repenting.

You only have to let the soft animal of your body

love what it loves.

Tell me about despair, yours, and I will tell you mine.

Meanwhile the world goes on.

Meanwhile the sun and the clear pebbles of the rain

are moving across the landscapes,

over the prairies and the deep trees,

the mountains and the rivers.

Meanwhile the wild geese, high in the clean blue air,

are heading home again.

Whoever you are, no matter how lonely,

the world offers itself to your imagination,

calls to you like the wild geese, harsh and exciting -

over and over announcing your place

in the family of things.

Mary Oliver, "Wild Geese"