A/N: This is not a Sugarverse story, for those of you following that universe.

John had left every lamp on, flooding the flat with yellow-white light that glinted off the few polished surfaces that remained uncovered, skittering over the ever present mess of papers tossed across the desk and coffee table.

Sherlock, barefoot and pyjama clad, squinted in the offensive light, caging his eyes behind his fingers. The headache didn't abate with the half-hearted darkness and he winced as he made his way around the living room, turning knobs or pulling chains until the dimness crept back in.

"All right, then?" John asked, sticking his head out from the open kitchen doors.

"Why did you turn all the bloody lights on?" Sherlock complained, throwing himself into his chair.

"Bit dark out today," John replied. The sky was low and grey, uncertain if it would make good on its threat of rain.

"Not that dark," Sherlock said. "You're going blind."

"I'm not," replied John, cheerfully. Sherlock scowled; the bright tone was as bad as the lights. His head ached, a tight line across the back of his skull, sending curling fingers of pain up his scalp.

"Tea?" John asked. Sherlock grunted in response – yes or no, John would discern the answer. There was a clattering in the kitchen that made him wince.

"Sherlock? Can you hear me?"

"What? Yes, I bloody heard you, you're not ten feet away."

"Tea then?"

"Yes," Sherlock sighed, tilting his head back. "Fine."

"Can't you go half a day without that ridiculous claptrap?"

"Claptrap?" John laughed.

Sherlock growled, raking his hands through his hair.

"Shut it off. There's only so much of their inane babbling and simplistic deductions I can take. Don't these shows have researchers? This is not at all how police procedure works."

"Something else then?" John asked. "Should be some crap programmes or a documentary, if you want."

"Oh, trying to educate me on the unnecessary details?" Sherlock asked, raising his hands to rub his temples, small circles of pressure against the dull ache that surrounded his eyes.

"A little knowledge never hurt anyone."

"Just shut it off," Sherlock sighed, narrowing his eyes at artificial brightness of the telly screen, at the too-vivid colours and the lighting that made the false reality too stark.

Merciful blackness poured over the screen and he sighed, relishing the darkness that seeped back in, the silence.

"You all right?" John asked.

"Headache," Sherlock replied. Predictably, John got up and returned with ibuprofen and a glass of water. With a muttered protest, Sherlock took them as John leaned down, examining his eyes.

"Intracranial pressure," he said.

"It's a headache, John," Sherlock sighed.

"Medical terminology," John replied with a laugh, patting Sherlock's shoulder as he moved away, the warmth of his fingertips fading through the fabric of Sherlock's pyjamas.

"Those weren't there before," Sherlock said accusingly.

"What?" John asked.

"The flowers." A splash of yellows and greens on the mantle, wedged between the knife he'd put there that first day and the skull, which had returned from one its outings to Mrs. Hudson's.

"Mrs. Hudson brought them," John replied. "She said the room could use some brightening up."

"It's bright enough already," Sherlock complained. "Why do you keep leaving all the lights on?"

"It's night out, Sherlock," John said, as if explaining a complicated concept to a child.

"When was she here?"

"A little while ago. You were sleeping."

"I was not."

"Yes you were."

"I was resting my eyes."

"You were snoring," John said with a smile.

"I don't snore."

"Oh yes you do."

He was in the bathroom in the middle of the night, wincing against the mirrored glare of the light, listening to running water. John was standing at the sink, wringing a flannel between his hands. He was silent, intent, as he moved in front of Sherlock, smoothing the cool material over Sherlock's face in light, slow strokes.

"Why are you doing that?" Sherlock asked.

"Quiet," John said.

"Yes, but why are you doing that?" Sherlock repeated.

"It'll make you feel better."

"I feel fine."

John ignored him, doing each hand in turn, frowning in concentration, twin lines drawn up his forehead from his nose. The repetitive motion was soothing, lulling him toward sleep.

"I must be dreaming," Sherlock said. "There's no other logical explanation."

John's chuckle was quiet, like a hum in the background, in the space between them.

He woke up in his bed, sheets tangled around his bare arms, the duvet shoved onto the floor so that he'd become chilly in the night. Sherlock struggled free and shuffled from the bed.

He'd been dreaming that John had washed his face and hands the night before, and no wonder. His pyjamas felt stale against his skin, old and stiff, and he wrinkled his nose when he sniffed the material. Into the hamper with them and into the shower with him.

The shower spray prickled hot against his palm and he stepped into the steam, inhaling deeply, feeling the dull headache finally fade to nothing, feeling the cold leech out of his skin.

When he reached out to pluck the flannel from the bar just outside the shower, it was still damp.

"John!" Sherlock snapped, striding into the living room, scowling. "John!"

No answer. The flat was silent in the way that indicated John wasn't at home, even upstairs engaged some quiet activity like reading or playing one of those mindless games on his phone. With a stream of inventive curses muttered under his breath, Sherlock shut off all the lights that John had so stubbornly left on. It was bright outside today, sun streaming through the windows, accompanied by a babble of voices floating up from the street below him.

He flung the windows open, sucking in a breath of fresh air, listening to the sounds of the city: traffic, horns, sirens that seemed closer than normal although he couldn't see any emergency vehicles on Baker Street, voices rising and falling, the sound of footsteps clicking under heels.

"I sent him out for a bit."

He jumped, hitting his head on the windowpane, cursing and spinning as he pressed a palm against the bright white flare in his skull.

"Oh, dear, I'm so sorry! I thought you'd have heard me on the stairs."

"Mrs. Hudson," Sherlock growled, biting his lower lip against more swearing that would only upset her, fisting his other hand to displace the pain, feeling the tug of tendons as his fingers curled.

"Oh, let me look," she said, putting aside the new vase of flowers she was carrying, waving him into his chair so she could fuss above him, tutting at his hisses and grimaces as her fingers prodded the top of his head.

"No bleeding anyway," she said. "You'll have a bit of a bump, if I'm any judge. John can look at it when he gets home."

"Why do you keep bringing us flowers?" Sherlock snapped. They were pinks and reds this time, less offensive than the yellow, but somehow too feminine.

"These aren't from me, dear," she replied. "Mrs. Turner next door sent them over. She thought the place could do with some cheering up and I have to agree with her. I'll just find a home for them. John shouldn't be long. He just needed some air."

"So do I," Sherlock growled.

"Oh, dear, are you sure?"

"Yes," Sherlock sighed. It would help with the headache, and her fussing wouldn't.

"He'll be here when you get back." That seemed important to her somehow, but Sherlock let it pass.

John wasn't there when Sherlock returned, head still aching dully, settling fatigue into his muscles, making it harder to run through deductions about other pedestrians. The flow of voices and the squeaking of shoes hadn't helped; the silence behind the front door was blessed.

But short lived.

Mrs. Hudson had left all the lights on, and the timer on the oven was beeping incessantly. Sherlock stalked into the kitchen, ignoring the lamps, and hit the button to stop the noise, pressing the pad of his thumb into it three times before it finally stopped its electronic whine so abruptly that he felt the relief as a physical sensation, making him sigh and lean against the counter for a long moment.

Sherlock shut off all the lights, wondering what the obsession was with having them on.

They're both going blind, he thought. He drew the curtains and changed before settling onto the couch with a glass of water and some painkillers. He remembered the thrill of cocaine, how it could dull everything – pain, uncertainty, loneliness, the desperate desire to have his mind slow down for even a moment. He could taste the memory so vividly, almost feel the needle in his skin, the drug sliding coolly into his veins.

The tang of tablets on his tongue and the tasteless water wasn't the same, but it was approved by John so he made do with that instead, closing his eyes and waiting for the slow relief to set in.

"Sherlock? Sherlock, can you hear me? Wake up."

"Oh for god's sake," Sherlock muttered, an arm moving to dislodge John's hand on his face.

"Let me check your head."

"You're as a bad as Mrs. Hudson," Sherlock complained.

"Worse," John replied. "She's not a doctor."

"At least you haven't left all the bloody lights on again," he sighed, rubbing a hand over his face as more skilled fingers probed his hair.

"Looks all right but you may have a headache for a day or so."

"I've already got one," Sherlock sighed.

"Some food will help. Chinese?"

"Fine," Sherlock agreed, swinging himself carefully to seated. The sounds of the street below seemed accentuated somehow, as if the conversations couldn't be blocked by mere walls and distance.

"Why is it so bloody noisy?" he complained, standing up to cross the room and shut the windows.

"I'll get the door," John said, closing them in, adding to the merciful quiet. "Anything in particular you want?"

"Get whatever you'd like," Sherlock replied.

"Harry's visiting," John said in the face of the obvious as his sister occupied Sherlock's chair, offering him a smile and a tip of her mug. "Hope that's okay."

"First thing in the morning?"

"It's already gone ten," John replied with a smile. "Not my fault if you sleep all hours."

"I thought John could use some company," Harry said.

"He's got me," Sherlock snapped. Jealousy was irrational, wasn't it? But she was in his space and John had left the bloody kitchen light on. "Did he do this when you were children? Turn all the lights on?"

"You get used to it after awhile," Harry sighed.

For two days there was a case, a glorious case, and his mind sang with the pure adrenaline joy of it. There was no time or space for anything but the deductions, the clues slotting into their proper places, sparking ideas, sending information whirling down dazzling synapses until it became clear and then – then there was the chase.

Through streets and alleys, over rooftops and fences, into a back garden once and out the gate where they were joined by an enthusiastic child until John stopped and returned him, protesting, to his bemused mother.

They were off again, London filling his lungs, each breath a symphony, a victory, bringing him closer to the apprehension, tackling a hefty male nurse outside of a hospital with no care for the mud and puddles of rain water, sirens in the background and the clatter of feet as he hauled his suspect up and shoved him gleefully toward Lestrade's waiting handcuffs.

"Brilliant work."

"Of course it was," Sherlock scoffed as the DI manhandled the suspect into the back of the car, shutting it with a definitive click.

"I'll get your statement when you're cleaned up."

"I'm fine now," Sherlock protested and was answered with John's laughter and Lestrade's smirk. His coat would have to go to the cleaners, as would his suit. There was a probably an enforced shower in his future, too, as well as a meal and orders to sleep.

He smiled anyway, if there had been a case, it meant the possibility of another one soon and no amount of John's fussing could change that.

"Just get some rest," Lestrade said, slipping into his car and shutting the door behind him.

The lights were on when they got home – not John's fault this time. Mycroft was sat in his chair, helping himself to some tea if the sound of the kettle boiling in the kitchen was any indication.

He smiled pleasantly, blandly, that infuriating knowing look in his grey eyes.

"You're looking well."

Sherlock stalked into his bedroom, slammed the door, and hid there until Mycroft went away.

He awoke sometime later, confused, the left side of his body warmer than the right, legs feeling caught up by the blankets and something else – something he'd never felt before.

It was John.

Lying alongside him, under Sherlock's left arm, his own arm draped over the detective's stomach and his legs pinning Sherlock's at the knee.

"John?"

The doctor stirred, tilting his head back, blue eyes blinking open.

"What are you doing?" Sherlock asked.

There was a sigh, a warm puff of air against the thin cotton of his pyjamas.

"I miss you," John said, the words distant in the darkness.

"What?" Sherlock demanded. "I haven't gone anywhere."

"I know," John said. "That's the problem."

John washed his face again in the morning and shaved him, which was odd. Surely he could do these things for himself? He looked down at his palms, scraped and raw from a fall he'd taken the day before on the case, asphalt tearing at the sensitive flesh. He flexed his fingers; they were stiff, but not so much he couldn't hold a razor.

He stopped John suddenly, hands holding the doctor's face in a cage of long fingers, and dropped his nose into the doctor's hair, inhaling deeply.

"You've switched shampoos." An accusation – it changed the way John smelled and he found he hated that, a sharp, sudden hatred that coiled in his stomach, made his mind burn.

"They didn't have my kind at the shop here," John said.

"Stupid," Sherlock huffed. "You should have gone somewhere else."

"Harry said she'd try and pick me up some," John sighed.

"Maybe she will," Sherlock replied, smiling, trying to be encouraging.

"Maybe." John was smiling back, but his eyes were sad.

Tea and toast helped offset the threatening headache and John – predictably – turned some of the lights on in defence against the low, overcast skies outside. He settled into his chair with a crossword book ("Three down: backcross," Sherlock said, earning a roll of the eyes that seemed more John and made them both smile) and Sherlock fiddled with his equipment. An experiment had been put on hold with the last case. Now with the lull, he could begin – unless Mycroft came back and forced him into hiding again.

But nothing worked quite right, his fingers clumsier than they should have been – an after effect of the road burn – and the light became too bright, the sounds around him too loud. The buzz from the light bulbs, the murmur of voices and traffic from the street outside, the scratch of John's pencil as he wrote or the tap of the eraser against the page as he thought.

Sherlock tried, and tried and tried, but the concentration had vanished like mist, impossible to grasp, never there when he looked for it. The headache crept in to take its place, a tightening vice against his temples, the knotting of muscles along the back of his skull.

He was on his feet suddenly, growling, the shattering of glass ringing his ears, nearly drowning John's shout and curses. Again and again and again until the table was swept clean and the failure was in pieces around him, separating him from John until the doctor cut a path through with shod feet.

"Sherlock!"

"Yes, I know my own name!"

"Calm down!"

"I'm fine, John! I'm fine! If you'd just let me think! If everything would just let me think!"

There were hands around his arms, pulling him through the wreckage into the living room, pushing him into his chair. Sherlock dropped his head into his hands, fingers curling into his hair, tugging to displace the pain, succeeding only in making it worse.

"You're all right," John soothed. "You're all right. I'll get you something for your head."

He didn't know what it was, but he took the tablets John pressed into his hand, wishing for a case instead, or for cocaine. He let John steer him to bed and tuck him in, sinking blissfully, gratefully, into the darkness.

He stayed there two more days, listening to the muffled voices beyond his door: John, Mrs. Hudson, Harry, Mycroft – Angelo? – and strangers, always strangers, his flat invaded by people he didn't know who wanted to know how he was, if there was any change. Sherlock buried his head under a pillow, ignoring them until they went away – he was none of their business, none of anyone's business. He needed a case and they had none so he hid. Hid from the noise, the light, the headache, until finally he slept again, exhausted.

It was the middle of the night and all the lights were on.

Sherlock stomped through the flat, shutting them off only to have them turn back on the moment he moved away until he was cursing, heedless of the hour, and John's clattering footsteps brought him down into the living room.

"What are you doing?"

"Why is it always so bright?" Sherlock yelled, spinning toward him, wincing in the glare. "Why is it always so loud?" The sound of voices from the street wouldn't stop no matter the time, conversations moving with squeaking soles, coming and going without any regard for what he wanted.

"I know you're scared," John said, hands on his arms again.

"I'm not scared!" Sherlock shot back. "Scared of what, John? I just want the lights to be off! Why must they always be on?"

"They aren't on," John said.

It was true.

The flat was dark, illuminated only by the faint orange from the street lamps outside so that John's face was more shadow than anything, deep lines made even deeper by the darkness.

"Sit," John said. "Just sit. It's okay."

"It's not okay," Sherlock hissed. "The light– the talking– this blasted headache– it won't stop."

"I know," John said. "I know. It's okay. I know you're frightened, but it's okay. It will get better."

"What will get better?" Sherlock demanded. "Frightened of what, John?"

There was no answer but John was crouched in front of him.

"You can't keep going away, it won't help."

"I haven't gone anywhere."

A sigh, such a soft sound in the darkness, almost masked by the footsteps outside, by the inexplicable electronic noises from the kitchen. John was holding his hands lightly, warmly, watching him with an expression Sherlock had never seen, couldn't identify.

"I know it doesn't matter to you, but I do love you. Has anyone ever said that to you before?"

Mummy, when he'd been small. He could still remember it, tender words spoken before he was old enough that they weren't appropriate or welcome any more. No one else. He shook his head, smoothing away a grimace at the dull pain.

"No," he said and found that it did matter. That somewhere there was a space for those words or that he made one and let them settle in.

"John, I–"

"It's okay, Sherlock. I'm not going anywhere. You're my best friend. I promise, I promise, I'm not going anywhere. I'm right here. I'll always be right here, okay?"

He nodded, uncertain, but John smiled slightly, blue eyes inexplicably bright, and Sherlock felt somehow better.

"Don't be afraid, all right?" John asked.

He could barely see for the glare when he awoke on the couch, stiff and sore, the headache pounding like a hammer behind his eyes, gripping his whole skull relentlessly. The sounds from outside were oppressive, filling every space around him, and a hand in front of his face did nothing to lessen the stark brilliance that bled through closed eyelids, making it impossible to see.

"John?"

"I'm here."

"John? Where are you?"

"I'm here."

In the impossible light, he tried to pinpoint John's voice – to his left, up the stairs. Sherlock rose on shaky legs, head ringing with each tentative step, reaching out and fumbling for the wall, following it to the stairwell.

"John?"

"It's okay, Sherlock, I'm right here."

"Where?"

"Here." A hand wrapped around his suddenly, warm and calloused and sure. Sherlock grasped hard in response, holding on against the possibility of being sucked back into the blinding light, into the flood of chattering voices and mechanical sounds.

"Come on, Sherlock. Come on. You can do it."

"Do what?"

"You're so close. Don't give up now. Come on, Sherlock. I know you can do this."

"John–"

There was a faint pressure on his hand, a gentle tug forward, and he took a hesitant step onto the stairs, careful not to lose his balance, not to let his grip slip from John's. He took another, groping in the light for the banister to keep himself steady, wincing, trying to see John around the light that cut through everything.

"John, I can't–"

"Come on, Sherlock, I know you can do this. I know you can. It's all right, I'm right here. It's all right."

He felt his world tilt to horizontal but John was still gripping his hand and he wasn't falling, not quite, cushioned by something soft beneath him and the rasp of cotton against his skin and the feel of John's fingers curled around his own like a tether.

"You can do this. It's time to come back."

Sherlock let out a deep breath, and opened his eyes.