When Sherlock got out of the cab, the first thing he noticed was the barking.

It would've been difficult to miss it. It echoed down the empty street, snapping at the edges of the pre-dawn quiet until it was all Sherlock could hear.

Beside him, John tensed and lifted his head, watchful and wary.

A small knot of police officers were gathered outside the front gate of an elegant house. Sherlock strode towards them, John trotting at his heels.

"Where's the body?" Sherlock demanded.

"See for yourself," Lestrade said, gesturing at the house.

In one of the upstairs windows, a silhouette of a person could be seen hanging by the neck.

"Excellent." Sherlock rubbed his hands together, eyes gleaming. "I want ten minutes with the scene."

"You'll have to wait like the rest of us," Lestrade retorted. "Unless you fancy going against that."

Lestrade nodded at the door. It was wide open and blocked by quite possibly the biggest Alsatian Sherlock had ever seen. Deep booming barks thundering from behind bone-white fangs, the dog stood with feet braced wide apart, hackles raised and mouth lathering.

"You haven't investigated the body yet?" Sherlock asked, scowling.

"God no. Every time someone tries to open the gate, the dog comes after us." Lestrade ran a hand through his hair tiredly. "We called animal control. They should be here in ten minutes."

"Then why did you call me here?" Sherlock snapped. "You don't even know that it's the work of our killer."

"It's a serial killer, Sherlock," Lestrade shot back. "We have to assume he's responsible for any new murders."

Anything Sherlock would have said was cut off by Donovan's sudden cry.

"Watson!"

John had jumped the iron fence and was slowly making his way to the front door. The dog roared and charged, teeth flashing in the early morning light.

A horrified sound escaped Sherlock's throat as he lunged for the gate. But what happened next froze him in his tracks - and got him crushed against the fence as several constables, fast on his heels and not expecting his sudden halt, piled en masse right into his back.

John dropped to his knees and let out a low bark. And the dog, that great hulking beast, skidded to a stop a mere meter away, gravel spraying outwards under its scrabbling paws.

If a dog could gape, Sherlock would have said the Alsatian was doing so with great prejudice.

It was in good company. Lestrade was staring, mouth half-open in an aborted bellow. Sherlock suspected he didn't look much better.

John lowered his head and whined, soft and crooning. The dog jerked, its ears raised and swiveling in uncertainty. Cautiously, it stretched its head forward and sniffed John's face.

John knelt patiently as the vicious cur first nosed his cheek, then started licking him. Delicately at first, then with greater enthusiasm, until the dog nearly knocked him over with the force of its affection. Laughing, John wrapped his arms around the Alsatian's neck and hugged it close.

"Buggering hell," Lestrade breathed out.

Sherlock could only agree.

"Christ," Donovan muttered. "He's nearly as much of a freak as you."

She spoke softly, meant only for Sherlock's ears. Lestrade, standing on Sherlock's other side, didn't even hear her.

But John flinched and twisted into a defensive crouch, dark eyes unsettled.

Interesting.

*

The New Place was strange.

It was hot and dry, a vast empty space devoid of life. Very different from the damp green fields of his birth, dotted with fat lazy sheep and shaggy cows. Or the concrete and steel of Home, grey and cold and full of bustling humans.

Even the sheep there were weird. Small and wiry, as tough and dusty as the land.

His Alpha had not come with him and the men in the New Place were unfamiliar. But they loved him all the same. Coarse hands petted him and rubbed his belly, slipped him bits of human food. There were no shortages of cots to jump and sleep on, curled around feet to keep them warm (the New Place was very cold at night and silly humans had no fur to protect them). He never lacked for companionship; there was always someone to curl up against or play with, and in the dark of night, secrets and fears were whispered into his soft ears.

And when he found the Bad Things for them, for his new Alpha, they were so proud that the smell of it nearly hurt his nose.

So no, it was nothing like what he was used to. The sun was too hot and the land too hard. But he had a pack and a purpose, brothers to look after and protect. And the New Place became Home and the Old Home was forgotten.

He was happy.

*

At first glance, John was a normal British bloke.

He liked tea and chocolate Hobnobs, and chips from the shop around the corner. He played rugby and laughed at videos of cats falling off of shelves.

He also talked to dogs.

Not in the Queen's English, no. He spoke to them in their own language, contorting his body into uncomfortable positions and making odd inhuman sounds.

A yapping terrier would quiet after one quelling look. A Rottweiler sat patiently while John worked a splinter out of its paw. On more than one occasion, break-ins that could have gone spectacularly bad succeeded because John was able to soothe an overzealous guard dog.

After a few strange looks and whispers, the Yard simply accepted it as one of John's quirks. Sherlock interrogated him ruthlessly. John shrugged and said there hadn’t been other children his age when he had been growing up and he had been practically raised by his family’s sheepdogs. It had been easy figure out their language. All he had to do was watch them. Sherlock should know, he got all sorts of information just by observing.

Sherlock couldn’t argue against that.

But still. There was times when John’s ability bordered on the supernatural.

"It must have been someone familiar to the victim," Sherlock said.

Lestrade crossed his arms. "Care to tell me why?"

Sherlock heaved a sigh. "Honestly, Lestrade, I know you’re moderately intelligent. The neighbors didn't hear anything when he was killed. If it had been an intruder, the dog would have barked. Therefore, someone close to the victim."

"Not necessarily."

Sherlock started and turned to the source of the mild interjection. "What?"

John shrugged from where he was sitting on the floor, a cocker spaniel curled in his lap. "She doesn't bark."

Sherlock frowned. "How do you know that?"

"She didn't when we came in, did she?"

Sherlock blinked slowly. Lestrade coughed into his fist to hide a grin.

"There are several police officers coming in and out of the room. It most likely didn't even notice us." Sherlock knew that statement was false even as he said it because all dogs noticed John.

John shrugged again. "Maybe. Doesn't change the fact that the dog doesn't bark."

Lestrade laughed outright. Sherlock gave him a nasty look and whirled back to the body, coat flapping behind him.

"Fine then. Someone, not necessarily known to the victim, came in through the upstairs window..."

As he spoke, Sherlock carefully slotted this incident into his mental file on John. There was something there that he wasn’t seeing. He needed more data.

*

It had been a normal patrol, one they had made many times in the past. He paced beside his Alpha in the crouching stalk of his breed, lowered head leading and tail tucked between his legs.

It was nothing, just the barest whisper of sound. But he hesitated for a fraction of a second and because of that, the bullet caught him in the shoulder instead of his head.

He howled as pain ripped through his side. Shouts and gunfire erupted around him as someone scooped him up and started running, jostling his hurt shoulder with every stride.

"God, sorry Johnny, it's all right. We'll get you fixed up, don't you worry."

His Alpha set him down behind a low wall. He struggled to his feet, because just before everything went red he had caught a familiar scent, and he needed to warn his pack brothers, they wouldn't be able to smell it, silly humans. But he couldn't move, something was wrong with his legs, he had to tell them-

"Easy, Johnny-boy, stay down. It's going to be fine."

The world exploded into fire.

*

In John's room, there is a single photograph.

It sits on his desk, framed in cheap wood and glass. A group of soldiers in full kit with grim determined faces, the Afghan sun high above their heads.

Hardly anyone ever notices the small border collie sitting at their feet.

*

An American patrol had found him in the desert. Unconscious, bleeding, and naked, surrounded by the bodies of British soldiers.

They couldn't figure out where he had come from, much less why he was wearing the collar of a military working dog. And when he had woken, the mystery got even deeper.

He couldn't speak or walk. He pawed at his ears and nose even though there was no visible injury. He had the motor skills of a toddler: poor hand-eye coordination, difficulty with grasping objects, and a lack of the most rudimentary dexterity. He didn't know how to write or wash himself, or do any of a myriad of simple human tasks.

His doctors hypothesized that he had been captured and tortured into a primitive state. It was decided to send him home for treatment where there were hospitals more equipped to give him the care he needed.

The trouble came in determining his country of origin. With his blonde hair and blue eyes, it was obvious he wasn't a native. There were a few soldiers matching his description in the MIA listings, and though several people came to see him, there were no positive identifications.

Finally, on the sheer basis that the collar he had been wearing belonged to a British dog, they sent him to England.

*

John hated doctors, Sherlock was surprised to discover.

A chase through Hackney had ended with a deep gash in John's arm, courtesy of their suspect.

Sherlock had been talking to Lestrade, giving him the final details he would need to close the case, when the paramedic had approached him.

"You Sherlock Holmes?"

Sherlock glanced briefly at him. "Yes."

"I was wondering if you could talk some sense into that friend of yours."

That merited a longer look. "What?"

The paramedic heaved a frustrated sigh. "Look, at the very least, he needs stitches and antibiotics. I wouldn't say no to a tetanus jab either. But the daft bugger refuses to go to the A&E. Keeps saying that he can take care of it himself."

"You're talking about John Watson," Sherlock said slowly. It wasn't entirely a question, but it wasn't a statement either.

"Mousy bloke with the great sodding cut in his arm? Yeah."

Sherlock and Lestrade exchanged baffled looks because the thought of John - level-headed and practical John, who was so sensible about eating properly, paying the bills, and keeping the toxins away from the food - making a fuss over something so reasonable was out of character.

"Where is he?"

John was sitting in the back of an ambulance and pressing a wad of gauze to his arm, face set in a mulish expression.

Sherlock stopped in front of him and cocked his head. "It's still bleeding."

"It's just a scratch. It'll stop on its own."

"I didn't realize you were qualified to dole out medical advice."

John scowled at him. "Don't you have a crime to solve?"

"I've solved it ages ago. And my idiot flatmate insists on letting himself bleed out, so here I am."

John glared at his feet. Sherlock took him in, noting the slight hunch in his shoulders and the lines of tension around his mouth.

"You're frightened," Sherlock finally concluded, with some surprise. John wasn't afraid of anything.

John looked away. "I'm not. I just- I don't like doctors."

"Why?"

"I just don't."

Sherlock furrowed his brow. "Is it a phobia?"

John barked a laugh. "You could say that."

Sherlock mulled that over for moment. "You do need to go to the hospital, John."

John flinched and turned his head away. "I know."

Sherlock hesitated, mentally flipping through his database of human behaviour for the proper response. "Would it make it better if I came?"

John blinked. "Really?"

"Don't ask stupid questions, John. I wouldn't have offered if I hadn't meant it."

"It'll be boring. We'll probably have to wait for hours before someone sees me," John said cautiously.

"Then you'll just have to entertain me."

Sherlock was rewarded with a blinding grin, and an unfamiliar lightness spread throughout his chest.

It stayed with him, even after they made it to the A&E and were finally admitted to a room. John sat stiffly as a doctor stitched up his arm, nearly snapping with tension. Sherlock started talking about a past case of his, one that involved three smugglers, a DI Gregson, and a rather baffled donkey.

By the time he was done, John was collapsed against Sherlock's side, helpless with laughter, and the doctor was staring at the two of them as if wondering if he should section them.

Hours later, Sherlock would still feel the warmth of John pressed up against him.

*

He was frightened.

He woke in a strange place in an unfamiliar body, senses muted and vision assaulted by violent splashes of color. People crowded around him, an incomprehensible jumble of sounds surrounding him from all sides as they jabbered at him.

He had panicked and lashed out. They subdued him and did something that made him sleep.

He quickly learned not to fight back because then they would give him something that made him sleepy and stupid. He tried to do what they wanted because he was a good dog, even though he didn't look like one anymore. Even though he couldn't understand what they were saying, his hearing dulled like his ears had been wrapped in cloth.

They poked and prodded him, forced him to use his new limbs. They talked at him a lot and he could only stare back at them dumbly. Terrified, confused, and afraid, and he couldn't tell them that, couldn't tell them that they were hurting him and he wanted to go back to his pack.

They found him hiding underneath his cot, bleeding from self-inflicted bites.

There was a long sleep and he woke in a small white room. The walls were soft and new people came in, forcing bitter pills down his throat and jabbing him with needles. They spoke at him too but this time he ignored them. He simply curled up in a corner and closed his eyes until they went away.

Eventually, they stopped coming.

*

Sometimes, when the burden of pretending to be human grew to be too much, John would retreat to his bedroom. He would turn the lights off and shed his clothes (false skins, he missed his fur).

In the drawer of his nightstand was a worn collar. Nylon webbing, two metal tags encased in rubber dampeners, plastic snap buckle.

John would fasten it around his neck and crawl into his bed, pulling the covers over his head. Curling in on himself, he would close his eyes and pretend.

Pretend he was still in Afghanistan, the wind ruffling his fur as the sun shone brightly in the wide expanse of sky. Surrounded by his packmates, sprawled next to a heater as the soft murmur of conversation passed over him, warmthpacklovehappy.

He felt half-mute in his awkward human body. No ears or tail to help him speak, only words. And humans lied, with their bodies and words, but how could he tell when he couldn't smell their deceit? So many times he had been fooled, because he was a dog and dogs had no use for untruths.

It was exhausting, trying to navigate the minefields of the human world. Most days, John felt like he was drowning.

Today had been particularly bad. Sherlock had sent him to interrogate a witness. The man had smiled and happily answered all of his questions, and John had returned to Sherlock with the information. Only for Sherlock to tell him, no, the man couldn't have flown to Australia and back in the same day, it was impossible. When they had rushed to his flat, all his possessions were gone and the man had disappeared.

Sherlock had berated him loudly right in middle of the Yard, the constables carefully not looking in their directions (they thought John was an idiot too, he could hear their whispers). After a sharp command to keep his clumsy oafish self from mucking up the investigation any further, Sherlock had stalked off in disgust. John had slunk home, and if he still had his tail, it would have been firmly tucked between his legs.

John snuffled and wiped his leaking eyes. Dogs didn't cry, and the first time he did he had panicked, convinced that his strange human body was broken.

There was a soft creak as his door opened.

John stilled, trying to pretend he was asleep. But his body shook with the force of his muffled sobs and he knew he wasn't fooling anyone.

The covers were pulled down, exposing him. John buried his face in his knees and squeezed his eyes shut.

Someone stroked his hair. "John."

John shook his head, nails digging red crescents into his arms. Then hands were uncurling him and drawing him up into a warm embrace. Burying his face in a solid chest, John cried.

Mycroft held him as he whimpered out his frustration and humiliation. Murmuring soothing nothings into his hair, the man waited patiently until John's sobs tapered off into exhausted silence.

Mycroft took out a handkerchief and gently wiped his face. "What brought this on, petit?"

John told him.

Mycroft pressed his lips together thoughtfully. "Yes, I suppose that was a rather silly mistake."

John whimpered brokenly. "I can't do this, Mycroft. I can't. I can't do this anymore."

He raked his nails across his face, hard enough to leave welts, and maybe if he tore off enough skin he'll find fur underneath.

Mycroft caught his hands. "Stop that, John."

"You should take me out back and shoot me. That's what they do with useless dogs, right?" John laughed, harsh and despairing. "Do they do that with people? It wouldn't matter, I'm not a person, I'm a dog."

"That's enough of that," Mycroft said firmly. He tucked John's head into his shoulder and John didn't resist. He stared blankly at the line of Mycroft's waistcoat.

"You've been human for a year, John. Quite frankly, I'm astounded by how well you are doing. You're very intelligent, more so than half of the people in this city."

"They would have known about Australia."

"You'd be surprised," Mycroft said dryly. "At any rate, they had their entire lives to learn about these things. You've only had a few months. It's understandable that there are gaps in your knowledge."

John closed his eyes. "I want to go back," he said in a small voice.

"I know." Mycroft hugged him tightly and pressed a kiss to his temple. "I know."

*

One day, a man came to see him.

He was different from the others. He didn't wear the dreaded white coat, nor did he carry needles or pills. He simply watched him, idly tapping his umbrella on the floor.

Whining fearfully, he huddled back in his corner and cowered. There was a soft rustle as the man walked towards him, then a hand gently carded through his filthy hair.

He looked up warily. The man smiled at him and said two words.

"Good dog."

*

Sherlock strode into the sitting room and stopped in his tracks.

John was fast asleep on the sofa, his head pillowed on Mycroft's lap. Mycroft was reading one of the journals Sherlock had left out, one hand idly petting John's hair.

"What are you doing here?" Sherlock growled.

"Checking up on John." Mycroft put down the journal and gave him a reprimanding look. "He was rather distressed."

Sherlock scowled, even as he felt a small twinge of guilt. "Maybe if he hadn't made such an idiotic mistake-"

"That argument doesn't hold much weight coming from someone who can't remember that the earth revolves around the sun, mon petit frere."

Sherlock sneered. "Don't you have some small country to conquer?"

Mycroft frowned lightly. "Don't be childish, Sherlock. But yes, I do have to get back to work. We'll have to continue this conversation some other time."

With far more gentleness than Sherlock was used to seeing from his brother, Mycroft disentangled himself from John. John whimpered in his sleep but Mycroft simply shushed him and slipped a cushion under his head.

Picking up his umbrella, Mycroft fixed Sherlock with a stern look. "Do try and take better care of him, Sherlock. He tries so hard to please you. It won't hurt you to be kinder to him."

With that, Mycroft left.

Sherlock glared darkly at the shut door. Shucking his coat, he made his way to the sofa.

John looked small. Which was strange, because short as he was, John carried himself with such quiet self-assurance that Sherlock had never considered him a small man. Frowning, Sherlock ran a finger along the collar buckled around his neck.

It wasn't the first time he had seen it. He had burst in on John enough times, often waking him from sleep, and had caught him wearing the collar on several occasions. He had wondered at its purpose but only idly. In his experience, people wore collars for very few purposes and he did not particularly care to go into his flatmate’s potential fetishes.

But now, after witnessing Mycroft's odd behaviour, Sherlock wondered if there was something more to it.

He didn't know much about John's past other than that he had been invalided out of the army. He didn't even know how John and Mycroft knew each other. Mycroft had simply appeared on his doorstep one day and told him that he found him a flatmate that might possibly last more than an hour. Sherlock had bristled at accepting Mycroft's help but after going through three flatmates in one month, he was getting desperate.

And John was perfect. He barely blinked at the body parts and experiments in the kitchen, didn't mind Sherlock dragging him off without any warning, and didn't laugh at Sherlock's social blunders. John didn't call him a freak or a psychopath, and growled at anyone who did. And he treated Sherlock with such warm affection that it made Sherlock's breath catch in his throat sometimes.

It didn’t make sense. People like John didn’t exist, and if they did, they belonged to people far better than Sherlock.

It was all very maddening. He knew there was something not right about John. It was constantly niggling at the back of his mind, all the more frustrating because he knew the answer was obvious. He just had to see it.

Carefully, Sherlock unsnapped the collar and slid it free of John's neck. John stirred slightly but didn't wake.

The tags were for an arms and explosives search dog of the 104 Military Working Dog Squadron. There was no name, just a serial number, but someone had scratched crude letters at the bottom.

JOHNNY

The collar was worn and frayed at the edges and Sherlock could feel the grittiness of sand embedded in the nylon. A spray pattern on one side - blood splatter? Perhaps John had been fond of the dog and it had perished in Afghanistan. Human sentimentality being what it was, John would have kept the collar. But why would he wear it himself?

There was a sharp intake of breath. Sherlock started and looked down to see John watching him with no little trepidation.

"John." Sherlock hesitated, stomach clenching at the wariness in John's face.

John hunched down into the sofa, eyes flickering nervously to the door. "Can- Can I have my collar back? Please?"

Sherlock held it out wordlessly.

John snatched it from him as if afraid Sherlock would change his mind and take it away from him. Scooting backwards, John carefully edged around him and skittered to the door.

"John."

John froze in his tracks. He didn't turn around as Sherlock approached him, though his back tensed with every step. Sherlock paused, then slowly placed his hand on his shoulder. He tried not to notice the way John flinched.

"You're not dull. Or an idiot." Sherlock paused, trying to find the words to fix this, because John should never be afraid of him. "I shouldn't have said that."

One blue eye peered at him cautiously over a shoulder, then John ducked his head and shrugged. "S'fine. I was stupid." He swallowed and curled in on himself a little. "I'm- I'm stupid a lot. Sorry."

"Don't," Sherlock said sharply. He regretted it immediately when John flinched again and took care to soften his tone. "Don't call yourself that."

"Sorry."

Sherlock shook his head. "Don't. You shouldn't be the one apologizing, John."

John actually looked at him at that, eyes wide with surprise. And there was an unpleasant twinge in Sherlock's chest because he never apologized to anyone, ever, but surely John knew he was different?

"I'm sorry," Sherlock said, gently squeezing John's shoulder. "I was a prat. You should have punched me in the face."

That surprised a laugh out of John. Sherlock smiled and rubbed the nape of John's neck with his thumb. He felt a small wave of relief when John leaned into his touch. "If I'm ever that horrible to you again, you have my permission to hit me. Will you forgive me?"

John glanced at him then lowered his head, giving a minuscule nod.

Sherlock watched John retreat to his room, mind whirring furiously. He had no illusions about himself. He knew he was cold at best and absolutely vicious when in the wrong mood. He had been bound to be cruel to John, it had only been a matter of time.

But in all honesty, he had expected John to fight back when he went too far. Under that quiet and easygoing nature, John had a core of solid steel. At the very least, he thought John would get angry and shout back at him.

Not to turn into this wary, frightened creature, braced for a blow and resigned to abuse.

Unpredictable, John was. Though this time, it was in a far less enjoyable way than Sherlock would have liked. It appeared he had triggered some hidden trauma, one that only Mycroft was privy to.

The thought of Mycroft knowing more about John made him twitch. He wanted to start looking, peel back the layers that made John who he was until he found every little secret. Until there was no part of John that was hidden from him.

But not right that moment. For now, he had take out to order and possibly one of those horrid Bond movies that John liked so much.

The mystery could wait.

*

The man - Mycroft, he was called - took him to his den.

It was a big den, all sweeping arches and heavy oak. There were countless rooms to explore, so many new things to investigate. Outside, there was a lush yard, perfect to nap or roll around in on a warm day. Mrs. Cole, the housekeeper, fussed over him and slipped him treats that Mycroft pretended he didn't know about.

The first few weeks, he had slunk cautiously at Mycroft's heels. He was in a strange den, after all, and he knew to behave. He didn't touch anything without permission, didn't sit on the furniture, lay obediently at Mycroft's feet when he was busy, and didn't make a sound.

He was terrified that if he wasn't a good dog, Mycroft would send him back to the Bad Place.

But Mycroft never hurt him. He was always gentle and spoke softly, petted him and let him sleep at the foot of his bed. Mrs. Cole stuffed him full of food and wrapped him in warm jumpers because he still wasn't used to the loss of his fur and got cold easily.

He settled into Mycroft's den. Cautiously, he started thinking of it as New Home.

Mycroft must have noticed because that was when the others started coming. Physical therapists, voice coaches, tutors - all to help him be human.

He had been frightened. He expected pain, being forced into uncomfortable positions and hurt when he couldn't understand. With every new face he had cowered and showed his belly, hoping that his submission would appease them enough that they wouldn't hurt him.

Mycroft stayed with him through the first sessions, a solid and reassuring presence. He replaced those that caused him too much distress until he found instructors he was comfortable with.

Slowly, laboriously, he learned.

The muddle of scribbles became letters and the letters became words. Vocal chords became sore as he learned to speak, forcing his tongue and lips into unfamiliar shapes. He learned to balance on two legs, clumsy fingers grasping at tables and walls for support.

At the advice of one of the physical therapists, Mycroft brought in someone to teach him how to fight. It was to help him become familiar with his new body, Mycroft explained. The man, a stony-faced SAS soldier, was unrelenting and ruthless. By the end, he was aware of every muscle and bone, knew the strength and limits of his new body.

(Later, he wondered if Mycroft had another motive in hiring the soldier because there were so many other things he could have done to learn to control his body. Sports. Dance. Hell, even yoga. But none were as useful in protecting Sherlock.)

He started exploring outside of Mycroft's den. Only a few streets away at first, careful to keep the house in sight. But he went a little further each day and it wasn't long before he was spending his days roaming around London, chatting shyly with baristas and doing the shopping for Mrs. Cole.

He became more comfortable in his own skin. But now that fear wasn't consuming his every waking moment and his human lessons were slowly tapering away, he was filled with restlessness.

He took up jogging (taking himself for a walk, he had nearly fallen over in shock the first time Mycroft suggested it). Then rugby, when a group of blokes playing in the park noticed his curious gaze and invited him to join in. The new activities helped but he still felt out of sorts. Like there was an itch deep beneath his skin, where he couldn't reach.

"You're bored."

He looked up, stopping his half-hearted mangling of a Rubix cube. "A bit. I'm rubbish at this."

Mycroft smiled and gently plucked the cube from his hands. "You just need practice. But I was talking about in general, petit."

He furrowed his brow in confusion. "I don't understand?"

"I've noticed that you spend most of your time outside these days. You wander around trying to find something to do." Mycroft canted his head. "You're dissatisfied."

He flushed and looked away. "I'm sorry. I don't mean to be ungrateful."

"Oh petit, I'm not angry with you." Mycroft carded his fingers through his hair. "Your breed needs constant stimulation, especially one with a military history like you. You're used to a high level of activity." He smiled ruefully. "I'm afraid my lifestyle it too sedentary to provide that."

He turned into Mycroft's touch and nuzzled his palm. "S'all right. I like it here."

"Yes, but you're not happy." Mycroft smoothed his hair out of his face. "Fortunately, I believe I have a solution."

He watched curiously as Mycroft tapped on his keyboard and pulled up a photograph on his computer. A tall, skinny man scowled at him from the screen, pale eyes glowering from underneath a mop of unruly black curls.

"This is my brother, Sherlock. And he needs you far more than I."

*

People thought John was the normal one.

Sherlock was so brilliant and cutting, always ten steps ahead of everyone else. He loved murders, the more gruesome the better, and kept body parts in the kitchen.

Compared to him, John was positively bland.

Except.

Except there was something slightly off about him. Like a vertebrae sitting just off center.

He could smell and hear things far beyond the capabilities of the average human male. John didn't think so, but Sherlock noticed that he could tell what Mrs. Hudson was baking from a block away and could hear Sherlock calling for him across a crowded crime scene. He was absolutely clueless about some things that any child would have known. Sarcasm and subtlety went completely over his head; some of the constables had made a game of mocking him to his face and seeing how long it took for him to catch on. (Sherlock had put a stop to it the moment he realized what was going on. Those same constables still flinched whenever they saw him.) And there were times when John would surreptitiously glance at the people around him, as if making sure he was reacting in the proper way.

It was barely detectable, the wrongness in John. Only Sherlock noticed. Scotland Yard, Mrs. Hudson, his rugby mates - they simply saw John as the affable, if dim, bloke. Normal to the point of being boring.

And as Sherlock watched John fool the rest of the world, he wondered.

What, exactly, was he trying to hide?

*

"John Watson. Remember, that's your name now."

"What if he doesn't like me?"

"He will."

"You said he gets bored easily. What if he gets tired of me?"

"Then my brother would be an idiot." Mycroft chucked him under his chin. "No matter what happens, you will always have a home here."

*

Everything started coming together, with Moriarty and the pool.

"You can talk, Johnny-boy. Go ahead."

John flinched so hard that Sherlock was half-afraid he'd set off the Semtex vest.

"Isn't he sweet? I can see why you like having him around. But then, people do get so sentimental about their pets. They're so touchingly loyal."

Moriarty couldn't see, what with the chokehold John had him in. But Sherlock saw the devastated look on John's face, as if he had lost something very dear to him and knew he would never get it back.

As Sherlock fired at the vest, the last piece of the puzzle settled in with a soft click.

*

He stared, mind still reeling from the barrage of words and deductions.

Sherlock was watching him with distinct disinterest, as if he couldn't care less how he responded. But his body was tense and facing slightly away. Defensive, ready for fight or flight.

"That's amazing."

A flicker of surprise crossed Sherlock's face. "Is it?"

"Yes," he answered honestly.

Sherlock had the look of someone who desperately wanted to believe in something but knew better than to try. And that was just wrong, because Sherlock was brilliant and extraordinary and wonderful, and he wanted to pounce on him and pepper his face with kisses until that hurt look went away.

But humans didn't do that. So he just smiled at Sherlock, warm and open.

Hesitantly, Sherlock smiled back.

*

Bleeding, bruised, his ribs aching with every breath, John dragged Sherlock out of the burning building. The man was unconscious, bleeding heavily from a gash across his temple.

Inside, flames licked at a battered nylon collar, lying abandoned in a changing stall. Plastic and rubber melted away and metal tags crumpled into charred lumps.

It was gone in moments.

*

His collar was gone.

He ransacked his room, desperation growing with every minute that passed. It had been in his coat pocket, he had been sure of it. He hardly ever took it out of his room, but with the bombings and Sherlock's increasing obsession with Moriarty's twisted games (Sherlock was drifting away from him and there was nothing he could do to stop it, he just wasn't interesting or brilliant enough), he had needed the reassurance. He didn't dare wear it, of course, but being able to feel in his pocket for the familiar nylon helped soothe his mind.

And now he had lost it.

Grabbing his coat, he dashed down the stairs and into the night. He could retrace his steps. Maybe it fell out somewhere.

Five streets over, he found it.

Nearly mindless with relief, he didn't wonder why it was just lying on the pavement in plain sight. Nor did he pay any mind to the noises coming from a nearby alley, of people trying very hard to be silent.

The last thing he remembered was a thick, strange-smelling cloth being shoved over his face.

*

Sherlock barged into Mycroft's office without knocking.

Mycroft frowned at him in mild rebuke. "I see you're feeling better."

Sherlock ignored him. "Show me," he demanded.

"You'll have to be more specific, Sherlock."

"John. He's not-" Sherlock stopped, hands clenched into fists at his sides. "What is he?"

Mycroft went very still. "I see."

Mycroft went to his safe. The real one, not the decoy that was obviously concealed behind the bookshelf. Taking out a thick file, Mycroft silently handed it to Sherlock.

Sherlock sat down and flicked it open. The very first page made the breath stop in his chest.

There were two pictures clipped to the top. One was of a blond man, solemn and weary, unfamiliar in that Sherlock had never seen his face so guarded.

The other was of a small border collie, white and tan, semi-erect ears up and alert. It almost looked like it was smiling, tongue lolling out of its half open mouth, warm blue eyes bright with intelligence and contentment.

"Most of the file is a documentation of his education. It makes for an interesting study in the development of language skills and learned behavior."

"Stop it." Sherlock rubbed his eyes furiously. "How did this happen? Did you make him?"

"Sherlock, contrary to what you may believe, I don't have the power to manipulate matter like that." Mycroft frowned at the file. "John's transformation is going to remain a mystery, I'm afraid."

"How did you find him?"

"My department, shall we say, observes some of the goings on in the Ministry of Defense."

Sherlock snorted. Mycroft politely ignored him and continued.

"There was an unusual case. An unidentified man wearing a MWD collar. He was found near the dog's unit. The soldiers were all deceased, but oddly enough, the body of the dog was never found." Mycroft tapped a finger on his desk. "It all pointed to an answer that seemed too fantastical to be true. I decided to see for myself."

Sherlock skimmed through the pages, eyes catching on one particular sheet. "They sent him to a psychiatric hospital."

"Yes." Something dark and angry slipped across Mycroft's face, gone so quickly that Sherlock might have imagined it. "They handled him badly. He was almost catatonic by the time I found him."

"Why?"

"He had turned from a simple-minded animal to a human, Sherlock, surely even you-"

"No. I mean why did you take him in?" Sherlock pinned Mycroft with a glare. "You brought him into your own home, used your personal resources to help him, and then let him move out." Sherlock narrowed his eyes. "You meant to give him to me, didn't you?"

"Perhaps."

"Mycroft."

His brother smiled at him, and there was something almost sad about it. "You were so lonely."

"I'm not." Sherlock looked away. "I wasn't."

He had long given up trying to connect with people. He was just too freakish, too strange. His peers all avoided him and whispered about him behind his back. Eventually, Sherlock found that it was easier not to make the effort in the first place.

And if he felt an odd pang sometimes, when he was alone in the dark and only a skull was willing to listen to him? It was nothing compared to the humiliation and hurt of having someone he considered a friend laughing in his face and asking how anyone could like the class freak.

Except John happened and now Sherlock couldn’t remember how to live without him.

"Dogs love unconditionally." Mycroft, as always, could read his thoughts. "I thought you could use something like that."

"So you trained him to like me," Sherlock said bitterly.

"Sherlock," Mycroft said, with such deep affection that Sherlock's eyes flew up to meet his. "If you think anyone can make John Watson do something he doesn't like, then you don't know him at all."

Sherlock stared down at the file. The dog smiled back at him.

"He loves you, Sherlock. And that was all your doing."

*

Sherlock.

*

John stumbled down the stairs, still groggy and muzzy with sleep.

He had not been nearly as lucky as Sherlock in the explosion and had spent the last week sleeping the sleep of the heavily medicated. Sherlock had woken him up periodically to force juice and toast down his throat.

It was the first time he had ventured out of his room farther than the toilet and he wanted a proper breakfast.

Sherlock was sitting at the kitchen table, hunched over his microscope. John ruffled his hair in passing and asked, "Tea?"

"Mm."

As John plugged in the kettle, a wooden box caught his eye. The engraving on the lid was distinctive, from a high-end jewelers. If John had to guess, he'd say it held a necklace.

"It's for you."

John started and turned around. Sherlock was watching him, face inscrutable as ever.

"Really? I mean, thanks." John scratched the back of his neck, confused. "Um, what's the occasion?"

"You survived your first criminal mastermind. It's quite momentous," Sherlock deadpanned.

John chuckled and leaned against the counter. "Is it really?"

Sherlock made an irritated sound. "Are you going to open it or not?"

John pretended to mull it over, just to see Sherlock bristle in agitation. "I suppose so."

Sherlock scoffed and turned back to his microscope, pretending he wasn't watching John out of the corner of his eye. Still chuckling, John undid the little catch and opened the lid.

Dark brown leather, thick and stiff with newness, steel buckle gleaming. A small titanium tag hung from the front, letters engraved in plain font.

JOHN WATSON

With trembling fingers, John flipped it over to read the back.

SHERLOCK HOLMES

221B BAKER STREET

LONDON

NW1 6XE

"You could wear it out if you'd like. No one will be able to see it if you button your shirt all the way up. I had it designed that way," Sherlock said casually.

John's fingers clenched around the strap. "I don't understand?"

Sherlock glanced at him briefly. "Your old collar was destroyed at the pool. As that was partially my fault, I thought I should replace it."

"Sherlock." John licked his lips nervously. "Do you- Do you know?"

Sherlock didn't look up from the microscope. "Yes."

John swallowed hard. "And you're all right with that? With me?"

Sherlock turned in his chair and beckoned him closer. John approached, stomach flipping nervously.

Taking the collar from him, Sherlock reached up and buckled it around his neck. He moved slowly, telegraphing each move so that John could stop him if he wanted.

John didn't.

The collar was an unfamiliar but comfortable weight around his neck. Sherlock slid two fingers underneath to make sure it was loose enough.

"You don't have to hide yourself from me," Sherlock said quietly. "I wouldn't want you to."

John flinched. "You don't- I have to, Sherlock. The things I do, they make sense to a dog. But they'll seem weird to you, or anyone else." He sighed and rubbed the back of his neck. "I'm just- It wouldn't be normal."

Sherlock chuckled, deep and fond. "And just when, my dear John, did I give the impression that I liked 'normal?'"

John blinked and looked around, as if seeing the flat for the first time. Strange chemicals bubbled on their kitchen table. The skull grinned at him from the fireplace, surrounded by stacks of forensic reports and crime scene photographs. Inside the refrigerator was a severed foot and a liver.

Sherlock gazed at him, grey eyes glinting with amusement and half-hidden affection. John started grinning, then laughing, because no, Sherlock wouldn't care if he was a dog or a man or a sodding unicorn. Sherlock was Sherlock, he was John, and together they were a pack.

Sherlock gave him one of his rare, happy smiles. Gripping the nape of his neck, Sherlock tugged him down and wrapped one arm around him in a brief embrace.

"You're my dog, John Watson. Never forget that."

*

He still missed being a dog.

He always would, he supposed. There were days when no matter how hard he tried, he just couldn't get a handle on the intricacies of human life and made a complete fool of himself. And others where he just hid under his bed for hours, biting viciously at his alien limbs and clawing his useless ears.

But Sherlock would snap at anyone who mocked him and clean his wounds. Sherlock touched him a lot more now - a ruffle of his hair, a stroke down his spine, a gentle squeeze on the nape of his neck (right over the hidden collar, he hardly took it off). Rewards were a quick embrace and a soft "good boy" whispered into his ear.

How he loved the man.

He barely slept in his room anymore, preferring to curl up at Sherlock's feet. Sherlock took to going to bed every night. Not to sleep - he spent most nights just lying on the mattress and muttering to himself. But Sherlock noticed that sleeping on the floor tended to give him a stiff back, so he relocated his nightly musings to his bedroom.

Oh, Sherlock was still as rude and demanding as ever. But he was also patient and took care of him when he couldn't watch over himself.

And life was never boring. They stalked the streets of London, their little pack of two.

He laughed, with the sheer joy of the chase and being alive. Sherlock was ahead of him - damn those long legs of his - and he followed faithfully.

Packmatebrotheralphahome.

Later, the murderer safely behind bars and his belly full of curry, he crawled into Sherlock's bed and sprawled over his legs. Sherlock ran a hand over his hair, quick and affectionate.

"Good dog."

John smiled and closed his eyes.