This is my first PotterLock, and probably my last. The inspiration for this came from Tumblr, and nobody seemed to be able to find a fanfiction like this. Despite their searches, it has probably been done a million times... Anyway, here's my take on this AU :3

Enjoy!

PS: I take no credit for anything or anyone you recognise.

There were flashes of red and green all around. John lifted his wand to curse a deatheater, hitting the masked figure square in the chest. The man before him crumpled to the ground. Satisfied that the hallway was clear, John turned and ran back to the great hall to join the main fight. He watched in awe as Molly Weasley cast a lethal spell on Voldemort's right hand man, Bellatrix Lestrange. He stopped for a second to appreciate the sight of the twisted woman fall to the floor. As he turned back around, he wasn't prepared. He didn't have time to cast a counter curse. "Sectumsempra" was the flash of light that hit him, sending him falling to the ground. His skin started to break up in long, deep scratches. It was as if he had been clawed by a lion.

John writhed in pain on the floor, blood soaking through his black shirt. "Please," he whispered into the air, "Please Merlin, let me live."

John Watson sat bolt upright in his bed at 221b Baker Street. "It was just a nightmare," he told his shaking self, sweat beading on his forehead. Afghanistan or Iraq? Sherlock had asked when they first met. Of course the genius would assume that it was one of the two, they were the only wars he had knowledge on. John couldn't exactly answer 'The Battle of Hogwarts' or 'The Second Wizarding War' without breaking the still-standing statute of secrecy.

Still sitting upright in his bed, John subconsciously reached for the scar tissue formed on his shoulder. According to the muggles, that was where John was shot. Only himself and a few others knew the real cause of the scarring. And it would stay that way. John had been in St Mungo's for years before he was ready to leave. He had been pronounced dead at the scene because his breathing was too shallow to detect and the beats of his heart were few and far between. It had been an hour later, when the bodies were being removed, that somebody realised that John was actually still alive. He was immediately apparated to St Mungo's for emergency treatment.

Many blood replenishing potions later, the physical wounds were healed. It had taken a year, but John's arm and shoulder was entirely usable again and contained minimal scarring. The curse had been left too long to counteract without a trace. It was a price they were willing to pay to save him.

Still, the psycological scars remained and John was deemed 'mentally unstable' and 'clinically insane'. Thus, he was kept on a psyciatric ward with others like him, many of them in medically induced comas to stop them from harming themselves and others around them. John found it extrememly difficult to get over the trauma – at first he felt like everyone was out to get him and would try to strangle or curse anyone who came near him. The nurses first tried to remove John's wand from him, but thought again when he began to aim stunning spells at them. Instead, they waited for him to be asleep and then substituted his wand for a fake one, identical to his own. It made him feel secure, even though it contained no magic whatsoever.

It was a whole year before John started to trust the nurses around him. It was another before he finally realised that the majority of people in the world were trustworthy. He began to remember the rest of his life, the auror training and the healer training. His school years, being a young Hufflepuff student with a bright future. He began to relax in his surrounding, willingly take his medication... After four years at St Mungo's, one for physical healing and three for mental healing, he was ready to leave. It was that moment that he swore he was done with magic.

He'd been living in the flat with Sherlock for a year now, and they'd solved many cases together already. John had kept true to his word – he hadn't so much as touched his wand since he moved in. It lay in the false bottom of a draw, probably gathering dust for all John cared.

Unable to get back to sleep, John walked through to the kitchen and made himself a cup of tea, barely batting an eyelid at the severed thumbs in a freezer bag that were sitting in the fridge beside the mild. It was an experiment, Sherlock had told him the day before. John had stopped questioning the man long ago, and merely shrugged at things like this now. Besides, he had seen much, much worse. Shuddering at the thought, John sat in his armchair and flicked on the TV. He smiled to himself as the news reported that a mass murderer in Scotland had been caught. Amycus Carrow, a known terrorist, apparently. John knew that all over the wizarding radio, they would be cheering at the capture of another deatheater. There were so few still out there now that they weren't acting up anymore. Many had tried to sustain a normal life, albeit in hiding from the aurors. The past was, however, beginning to catch up on them. They had caused too much harm to be allowed to walk free.

It was an hour before Sherlock awoke from his room and came plodding through. It was another two hours before the dark haired man spoke. It was like that most mornings. John would awaken from a nightmare first and make a tea, then Sherlock would wake up and lie on the long sofa, fingers pressed together and eyes closed while he assessed his mind palace, completely oblivious to the world around him. It was at that point that John would make his flatmate a cup of tea, and Sherlock would momentarily break his concentration to sip the hot liquid he knew was there without actually acknowledging it's arrival.

This suited both perfectly. John got to read the newspaper or watch the television and Sherlock got to... do whatever it was Sherlock did of a morning. When he finally spoke, it was to thank John for the tea. "You're welcome," John replied subconsciously. They never spoke much of a morning. John busied himself by getting washed and dressed, while Sherlock examined an eyeball at the kitchen table. London had been extremely quite, crime wise, recently. All crimes were small – the latest was a jewelery shop robbery with clear CCTV footage of the thief. It suited John, but Sherlock was on edge. It had gotten to the point that DI Lestrade had ordered the mortician, Molly, to give Sherlock random body parts to quench his thirst for knowledge, in the vain hope that the mastermind wouldn't turn to crime himself.

By teatime, Sherlock was dissecting the eyeball messily on that morning's newspaper. John just shook his head and settled on the sofa for some afternoon television. About half an hour into a show, Mrs Hudson called up the stairs. Usually, when her voice was heard, it was because Sherlock and John had a client. It was, however, extremely unusual that she would call John instead of Sherlock.
"John, there's someone at the door for you!" she called up the stairs. John stiffened slightly in his chair.
"Who is it?" he called back, hoping for the life of him it wasn't a remnant of his past. A deatheater wanting revenge.
"She says her name is..." there was some mumbling, as if Mrs Hudson was getting the visitor to repeat something, "Minerva McGonagall?" John's heart missed a beat as he stood.
"Send her up," he called in answer.

It had been a year since John had spoken to the Hogwarts professor, now Headmistress. He smiled slightly as he saw her climb the stairs elegantly, her greying hair twisted into the familiar tight bun on her forehead. She was wearing an emerald traveling cloak, which had recently seemed to come into fashion for muggles. John would have thought this woman was extremely strict, if it weren't for the warm smile on her face. "John," she said fondly, "It's so good to see you again!"
"Professor," he grinned back, giving her a one armed hug, "It's been too long,"
"Yes, well, you did seem to disappear for a while!" she said, a slight stern tone to her voice.
"I did what I had to do, Professor, you know that," he answered quietly.
"Oh, I know, John," she smiled sadly, "And stop calling me 'professor', I'm not your high school teacher!"
"Anymore," he grinned.

They sat opposite each other, McGonagall on the sofa and John in his armchair, which he had turned to face her.
"Are you planning on returning to the-" McGonagall began, but John coughed and cut her off. She was about to say 'Wizarding World' when Sherlock walking in to the living room. She raised an eyebrow at John, obviously trying to subtly ask if they were together. John gave her an exhasperated look and shook his head.
"I'm not gay, Minerva." he said flatly.
"You keep telling yourself that, dear," she winked jokingly. John just rolled his eyes.
"Sherlock, this is my old teacher, Minerva McGonagall." John introduced them, "Minervra, this is Sherlock Holmes, my flatmate."
"Boyfriend," Mrs Hudson could be heard calling up the stairs. Sherlock said 'hello' politely and then excused himself, without denying that himself and John were a couple. John could tell that a blush was creeping on to Sherlock's face as he walked to his room.

"Sherlock doesn't know," John said quietly.
"About any of it?" McGonagall asked sadly. "Not even the-" she gestured to the shoulder.
"He thinks I was shot in Afghanistan," he answered, "And that's how I want to keep it."
"But, he deserves to-"
"No, McGonagall, I decided that I was done with all of that last year. I vowed to forget everything and live an ordinary life." John said sternly, in a way that would have made him seem an awful lot like McGonagall herself.
"And this is ordinary?" she looked at the thumbs and eyeball on the table.
"My flatmate is a high functioning sociopath with a hobby of experimenting on body parts," John shrugged, unfazed as if he told everyone this on a daily basis, "Besides, it's not like he's doing anything illegal – as far as I'm concerned, it's perfectly okay for him to be supplied with the digits of dead people with a court order."
"Right, so you're living a quite life now," she sighed, "So there's no chance of you completing your healer training and returning for a while?"
"I'm not ready for that, not yet." he answered, "Maybe in a few years but... I can't go back to how it was before the war. I don't want to ever be in that situation again."
"That's understandable, John, but if you ever want to get back in, there will always be a place for you at Hogwarts," she smiled fondly at John, "I'm glad you're doing alright."

McGonagall's visit had left John wondering if he had really made the right decision to completely leave magic behind. He silently wondered whether he would be able to remember any spells after being away for so long. He stood with his desk draw open, contents strew across his bed and the false bottom lifted away. Lying in the bottom of that draw was a clump of parchments – his Hogwarts letters from years 1 through 7, and his OWL and NEWT results (Outstanding and Exceeds Expectation in all but his Divination OWL, which he got an Acceptable). Lying on top of this stack was a trophy of sorts – Order of Merlin, First Class – which he received for his efforts in the War. Tucked away at the back, completely out of sight, was what looked like a stick. It was mahogany, eleven and a quarter inches, with a core of unicorn hair. His wand. Just lying there, with a thick layer of dust.

It took John five minutes to build up the courage to lift it from it's spot. The minute his fingers curled around the wand, he felt the magic surge through him and the memories it contained return. He cast a simple levitating spell, Wingardium Leviosa, to get the feel of things again. He made a pair of socks float across the room and land on his bed. John couldn't describe how he was feeling at that point. It was like a weight had been lifted off him as he started to produce harder spells with a great deal of accuracy. Magic is like riding a bike, he thought, you never truly forget.

John lay on his bed, lazily practicing his magic. He had replaced the false bottom and the contents of his draw, leaving only his wand out. He thought for a moment before thinking of a spell to try that wouldn't get him in to trouble. He smiled slightly, suddenly thinking of Sherlock, and it hit him. The next spell he wanted to try? A patronus. He hadn't been able to produce one since before the war, and he knew it took the shape of a large hedgehog. Thinking carefully about his happiest memories, he cast the spell. At first, there was nothing but silver mist. The second time, a long shape was formed. It wasn't round enough to be a hedgehog, and John was confused. The third and finally try, John thought about the man downstairs, driving himself mad with a lack of crime, probably talking to his skull. The patronus that was formed from this took a full shape. It wasn't a hedgehog at all, but a sleek otter. It scuttered all the way around the room before vanishing by the door as it opened.

John jumped, stowing the wand quickly under the duvet, having not expected the interruption. Sherlock stood in the doorway, a huge grin on his face.
"What is it?" John asked, "Has there been four identical serial suicides and this one's left a note?"

"Not at all," Sherlock sat on the edge of John's bed, wrapping an arm around his shoulder.
"Then, what?" John furrowed his brow, confused by Sherlock's intimacy. They rarely touched, let alone hugged.

"I'll tell you, if you promise to tell me what all that silvery mist was a minute ago," Sherlock smiled smugly.
"Certainly, if yours lives up to my expectations," John replied, just as smugly.
"I've just realised I'm in love," Sherlock said, leaning his head on John's.
"Huh?!" John felt alarmed. How was this possible?
"I'll rephrase that," Sherlock chuckled, "I've just realised that I'm in love with you, and it feels wonderful." John was speechless.
"I... er.." he didn't need to speak though, because Sherlock planted a warm kiss on John's lips. He was startled for a second, then melted into it, closing his eyes and enjoying the feel of the soft lips against his own.

When they broke apart, Sherlock just smiled. "Did I exceed expectations?" he asked, obviously not realising his reference to the grades of the Wizarding world.
"Outstanding," John replied, a slight smile on his lips.
"Your turn, John," Sherlock looked more than eager.
"It used to be a hedgehog, but it's changed." John uncovered his wand. "It seems to be an otter now..."
"What-?" Sherlock asked, confused, as John held up his wand.
"Expecto Patronum," he whispered, barely loud enough for Sherlock to hear. The man watched in amazement as a silvery blue otter burst out of the tip of the wand, it's form stronger than before. It seemed to wait for a moment, looking back at John, as if waiting for something. And then something remarkable happened.

Both John and Sherlock watched in amazement as another animal shot from the wand, this time with a back full of prickles. "My hedgehog!" John exclaimed happily. The otter and the hedgehog played together before they vanished. Sherlock didn't bother to question the fact that John had just performed magic right in front of him. In fact, he just leaned against John, tangling their hands together.
"If you're the hedgehog, does that mean I'm your otter?"

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