This is inspired by the 30 day OTP challenge from Tumblr.

I had actually finished a different first chapter when I thought how fun it would be to to a Potterlock 30 day OTP instead, and... well, here it is. I'm hoping it will encourage me to stop agonizing over everything that I write and push me to publish things more often, because I'm terrible at that.

Things are going to be pretty kid-friendly for a while, but I am planning on eventually rating this as a "Mature" fic, so be advised if that's not your cup of tea. You can also read this over on Ao3 under the same username. Hope you enjoy!

1. Holding Hands

Sherlock eyed the barrier between platforms 9 and 10 nervously. It seemed very solid, and Sherlock wondered again if he wasn't the victim of an extremely elaborate hoax.

It had to be real, it just had to be. Only a month and a half previously a man with a long white beard and twinkling blue eyes had shown up at his door, wearing a funny purple suit that made Sherlock's father raise one eyebrow. The man had invited himself into their parlor (Sherlock still wasn't sure how he had managed it), and handed him a thick envelope with his name written in green ink. Inside was a letter, which read:

Dear Mr. Holmes,

We are pleased to inform you that you have been accepted at Hogwarts School of Witchcraft and Wizardry. Please find enclosed a list of all necessary books and equipment.
Term begins on September 1. We await your owl by no later than July 31.

Yours sincerely,

Minerva McGonagall
Deputy Headmistress

There had followed a number of pages telling him to buy things like plain work robes (black), a cauldron, a load of books with odd titles like One Thousand Magical Herbs and Fungi (which Sherlock had already devoured), and, most extraordinarily, a wand. Sherlock had tried a few simple spells, and they seemed to work. One particular charm had allowed him to unlock Mycroft's bedroom door and leave a dead sparrow under the nightstand, which was intensely satisfying.

His father and mother had protested. Sherlock was meant to go to Eton like his brother, not some freak school in the north. And, oh, how Sherlock had wilted at hearing that word that had previously fallen only from the mouths of his tormenters at school.

Now, standing on the platform, Sherlock nearly doubted himself. But surely it couldn't all have been faked? The secret alley in London with all the wonderful shops, surely that was real?

He closed his eyes and steeled himself, pushing his trolley forward. He was nearly at the barrier, two feet away, one foot away, and then –

There was a rush of warm air as he stepped forward into open space. He glanced up and gaped to see a sign that read in official gold lettering, "Platform 9 3/4." He'd done it.

The Platform was teeming with people. The children seemed to be dressed normally, but the adults were mostly wearing robes of varying styles and colors. A barn owl whizzed inches over his head and Sherlock ducked, watching as it flew away to perch on the outstretched fist of a man with shocking lime-green hair. Sherlock straightened and let out a shuddering breath. What now?

"You a first year, sweetie?"

Sherlock jumped and spun to look at the person next to him, a stocky woman with dark blonde hair and laugh lines around her blue eyes. She was wearing creamy white robes and a bright yellow hat, and Sherlock thought she looked like a bit like a fried egg. He nodded warily at her.

She smiled. "Muggle born?" she asked kindly.

Sherlock bristled. He didn't like the feeling that other people knew more than him about anything, and despite the fact that he'd only joined the wizarding world a few short weeks ago, he already felt he was at a disadvantage for not being born into a magical family. "Yes," he said shortly.

"Oh, don't worry about that, dear, you'll do just fine! My John can show you what's what, he's – Oh!" she threw up her hands in exasperation. "He's disappeared again. Embarrassed of me, I expect."

Sherlock stayed silent.

"Well, I can help you, in any case. You just take your luggage over there and they'll load it up for you, have you got it all labeled? Yes, of course, I see you have, good boy. You'll have to change into your robes on the way, have you got them with you?"

Sherlock nodded and tugged on the strap of his knapsack.

"Oh, good. Your mother certainly didn't leave you unprepared, did she?"

My mother has nothing to do with it, Sherlock thought bitterly.

"Well, you just get your luggage taken care of and get on the train then. There'll be plenty of people to meet, so you just have a good time." She smiled and pinched his cheek, missing Sherlock's expression of horror. "And if you see John Watson, you tell him to write to his mother!" she trilled, giving him a slight push.

Sherlock nodded and walked forward, slightly dazed by the interaction. He handed his trolley off to the station attendants (watching with fascination as they levitated his trunk into the car) and boarded the train. He'd already made up his mind to find an empty compartment and settle down to read the book he'd brought with him: Hogwarts, A History. It wasn't technically required reading, but it had looked fascinating and he was keen to catch up on anything his classmates might already know.

He was starting to despair of finding an unoccupied compartment when he finally spotted one near the end of the train. He immediately dropped down in the seat by the window, placed his bag in the seat beside him, and slouched down, propping his feet up on the seat opposite. He pulled out the heavy tome from his pack and buried his nose in it, satisfied that he was broadcasting a perfectly unfriendly demeanor.

He had just begun to read about the enchantment of the Sorting Hat when the door slid open and a boy with blonde hair poked his head in. "Er, mind if I join you?"

"Yes," Sherlock said tersely, not raising his eyes from his book.

"Too bad then. Everywhere else is full," the blonde boy said dryly, falling with a sigh into the seat beside Sherlock's feet. "Is that a good book?"

"Yes."

Both boys sat in uncomfortable silence for a few moments, the blonde boy fidgeting and Sherlock trying and failing to ignore him. Finally the blonde boy blurted out, "I'm John, by the way. John Watson."

Sherlock blinked and looked at him properly. Yes, the family resemblance was clear now. Same blue eyes, same nose. "I met your mother."

John blushed. "Did you? Sorry."

"No, it's fine." Sherlock studied him for a moment. "She told me to tell you to write her." John's face grew even redder, and Sherlock grinned despite himself. "I'm Sherlock Holmes."

John chuckled. "Now that's a wizarding name. I don't know the Holmeses, though, where are you from?"

Sherlock blinked and stared at him. "My parents are muggles," he said tersely.

"Oh." John looked surprised. "It's just, Sherlock's such an unusual name I thought you had to be from a wizarding family. My middle name's Hamish, after my dad." He wrinkled his nose. "You have any idea what house you'll be in?"

Sherlock shrugged. He wouldn't admit it, but the idea of Sorting made him exceedingly nervous. What if it went wrong? What if he didn't fit anywhere, and the Hat just sat there and never made a decision until they decided it was better to send him home?

"Mum and Dad want me to be in Hufflepuff. They're both Puffs." John raised one shoulder in a lop-sided shrug. "We'll see."

Sherlock didn't say anything. He did not want to be in Hufflepuff. The other houses didn't seem that bad, except maybe Slytherin. It had been intriguing until he'd read about Salazar Slytherin's dislike of muggle-borns.

John was busy fumbling in his pocket and he fished out a pack of cards with a triumphant grin. "Want to play Exploding Snap?"

An few hours later, Sherlock was laughing madly. The cards burst and fizzled if left too long out of someone's hand, and it was a race to throw down their cards as fast as possible before they exploded in their faces. Sherlock had soot on his cheek and John's right eyebrow was slightly singed, but they were both grinning like fools.

During that time Sherlock had decided that John wasn't so bad, as people went. He didn't ask stupid questions, and when Sherlock shyly asked him about life in the wizarding world his answers didn't patronize. It was brilliant. Sherlock would almost put up with being a Hufflepuff if it meant he and John could be friends.

John had also bought a mountain of food from the witch at the trolley, which he'd bullied Sherlock into trying. The chocolate frog had been quite good (he'd given the card, Imhotep, born 2648 BC, to John), and the Every Flavor Beans had been diabolically entertaining.

Another bang went off in John's face and he giggled, slipping down to lie on the floor of the compartment. "Pass me a Peppermint Toad."

Sherlock grabbed one off the top of the dwindling pile of sweets and tossed it to John, who caught it deftly in one hand. Sherlock looked out the window at the darkening sky. "We must be nearly there."

"Nn?" John grunted and propped himself up. "Guess we better get changed."

They scrambled haphazardly into their school clothes, and not a moment too soon. The train had begun to slow, and John smiled nervously at Sherlock. "Ready?"

Sherlock shook his head. "No."

John giggled. "Yeah."

They were met outside the train by an absolute giant of a man with a bushy beard and coat that looked like it was made of thousands of bulging pockets, all sewn from slightly different materials as if they'd each been added when the last ones were filled. The man introduced himself as Hagrid and led them down to a dock at the edge of a smooth black lake where dozens of little boats were tied. "Two to a boat!" the giant called gruffly, "Don't worry about paddlin', they take care 'o that themselves!"

Sherlock settled gracefully into one of the boats, smirking when John fell in clumsily. Once everyone was seated, the boats began to glide forward of their own accord, slowly making their way towards a tall castle at the other end of the lake.

Sherlock nearly had to laugh at the ridiculousness of it all. This didn't just happen, there weren't magical castles in real life. Instead he looked over his shoulder, grinning at John's gaping face in the lantern light.

Soon the boats were bumping up on the opposite shore, and the students began clambering out of them. Hagrid led them in through an impressive set of doors and handed them off to a stern-looking woman with square glasses.

"Welcome to Hogwarts," she said in a crisp Scottish accent. "I am Professor McGonagall. In a few moments you will pass through these doors to the Great Hall, where you will join your students. But first you will be Sorted into four houses…"

Sherlock tuned himself out. She didn't seem to be saying anything he didn't already know. He busied himself by looking at his surroundings. There was a huge tapestry on one wall, and Sherlock's jaw dropped in surprise as a unicorn poked its head out from behind a woven tree, blinking its stitched eyes at him. He swallowed and stared as it pranced across the tapestry and disappeared into the foliage. He felt a sharp poke in his side and turned to see John staring up at the ceiling. Sherlock followed his gaze and let out a small gasp.

There were staircases above their heads, but they seemed to be moving, rotating. How on Earth is one meant to find their way to class? Sherlock thought with despair. Suddenly he felt a tug on his hand.

"We're going in, Sherlock!" John hissed, pulling him forward. Sherlock followed, keeping hold of his hand.

The Hall was huge, with four long tables that ran perpendicular to a fifth along the farthest wall. Sherlock's cheeks grew hot as he felt the eyes of a hundred students landing on him, and he set his shoulders defiantly, holding his head high as they walked down the aisle towards a stool where a battered pointy hat was sitting in a heap.

Professor McGonagall pulled out a long roll of parchment and read out in a clear voice, "Albert, Amaryllis!"

A tiny girl with messy hair stepped forward, shaking as she sat down. The Hat had only been on her head for a few seconds when it shouted out, "Ravenclaw!" The girl grinned and jumped off the stool, walking quickly towards one of the tables in a burst of applause. Sherlock swallowed and felt John squeeze his hand. Not long now.

All too soon McGonagall called out, "Holmes, Sherlock!"

Sherlock took a deep breath and released John's hand with reluctance. He walked forward, frowning slightly at the hat as if he could intimidate it into putting him in the right house. He sat down and the hat slid down over his eyes, thankfully blocking out the curious faces that stared at him.

There were a few seconds of silence before a sly voice chuckled into his ear, "Well you're certainly not a Hufflepuff."

Sherlock couldn't help a small grin. No, I'm not, he thought back.

The Hat chuckled again. "You're a difficult one. Very bright, I can see that, and not lacking in courage either. And you're competitive, too, really want to prove yourself… where shall I put you, where oh where?"

Sherlock grew more and more nervous as the Hat continued to mutter. He'd been sitting here for a long time now, minutes at least, and he was starting to hear whispers spreading around the Hall. What if I don't belong anywhere? He thought desperately.

"No no, you belong somewhere, it's just a matter of deciding," the Hat purred.

Then make up your mind! Sherlock snapped.

"Well calm down there, sonny boy, it's not my mind that needs making up, it's yours."

Sherlock fought the urge to slump and put his head in his hands. Just… don't put me in Slytherin.

"Why ever not? You could do well there, lots of ambitious young minds there. Why ever not?"

They don't like muggle borns there. I'll have no friends, Sherlock thought before he could stop himself.

"Ah…" the Hat sighed. "Friends, that's a telling word." The Hat was silent for a moment. "You need looking after, boy. Better be GRYFFINDOR!" the Hat roared the last word out into the Hall.

Sherlock felt weak with relief, and he tugged the Hat off his head and made his way to the table that seemed to be cheering the loudest. He slumped down into the first available seat, wincing as a couple of older students thumped him on the back. He ignored their congratulations and turned to watch the rest of the Sorting.

At length, they made it to the end of the alphabet. John was one of only two students left, and his name was finally called. John looked pale as he stumbled up the steps to the stool and pulled the hat onto his head. It sat there mumbling for about fifteen seconds before shouting "GRYFFINDOR!"

Sherlock couldn't help beaming as John skipped over to join him at the table. John's face was pink with happiness. "Thank Merlin I'm not a Hufflepuff," he laughed into Sherlock's ear.

Sherlock giggled. "Glad to be a Gryffindor?"

"Oh yeah," John whistled.

Later that night Sherlock was lying spread-eagled on his bed, listening to John moan a few feet away. "I told you not to eat so much," Sherlock yawned.

"Shut up, shut up, Sherlock, I swear…" John groaned and curled up on his side.

Sherlock couldn't stop himself from smiling. He didn't think he'd ever been so happy. He had felt ill fitted to the world for so long, but no longer. At least for the moment, he felt as if he were in the right place.