John Watson stood anxiously upon the platform nine and three quarters, heart still hammering from the decisive lack of impact. Dumbfounded, he stared around at the billowing smoke, flicking robes and most noticeably, disproportionate numbers of hooting, screeching owls. He had presumed that the station would be a come-down after Diagon Alley; however, he had indeed been quite mistaken.

His wonder was brought to an abrupt end as he turned to find Harry watching him smugly. He remembered the bet and groaned.

"You owe me a galleon," Harry declared.

"No, I don't."

"Yes you do, you've got that expression again, you're-"

The two were jerked back to the situation at hand by a word of caution from their mother, a short, educated lady in her mid-forties, and the family wound their way through the crowd, their father pushing the trolley containing the children's luggage. They halted a small distance from the edge of the platform, where they embraced and said their final goodbyes before the two adults helped heave the trunks onto the train.

"And do try to keep out of trouble, Harry!" the woman called.

John felt a brief irritability prickle his stomach; of course, nobody warned him of the same. He had always been the sensible sibling and was neither as audacious nor as inexorable as Harry always had been.

Upon boarding the train, an encompassing anxiety overtook him and he felt compelled to run back and bid his parents a forth goodbye. He resisted the temptation, however, and dragged his trunk through the bustling train, made difficult by his leg, until he reached an empty compartment- or at least, he had thought it empty, until he opened the door to find a small, dark haired boy sitting behind the door, who neither looked up nor gave any inclination he was aware of John's presence.

In truth, John had little fancy for company during long journeys- although well rehearsed in small talk, he found he seldom had enough in common with strangers to occupy any great length of time- but having committed to entering the compartment, manners inclined him to remain.

"Uh, hello," he said, giving a hesitant smile. The boy looked up slowly, first at John's feet then upwards until he met his eyes. "You wouldn't mind-" he let his voice trail off when the other's attention turned towards John's wrist, where his gaze locked. John cleared his throat nervously. He couldn't help feeling that he was awaiting a judgement of some kind.

"First year, muggle born, middle-class family. Sit down, rest your leg. Not that it needs it."

John stared, dumbfounded. "What?"

"You have a psychosomatic limp. Ever seen an explosion? Terrorist attack?"

"We haven't met, I... How do you know me?"

The boy looked back down at the notebook, then spoke rapidly without looking at him. "Oh, I don't. Though I do know that your mother is a doctor and that you have a small dog, probably a terrier. And that your real father died, though not recently, most likely long enough ago for you not to recollect him or at least not with any real clarity. Though you remember how he died, don't you? Do try not to, you're making those memories up."

For a moment, John stared at him, heat rising. Then, "who the hell are you?"

The other's gaze flicked up to meet his momentarily before looking back down at the book. His eyes were rather pale, and John couldn't help thinking there was an odd emptiness about them. Then the situation seemed to click into place.

"You're a wizard. Of course you are, that's how you know this, right? A spell."

No response. He supposed he shouldn't have been so surprised in the first place. "You already know magic, then? You from a magic family, or..."

"Half blood."

"So, how do you...?"

"Legilimens," he said dully. He sounded slightly off, but John was fascinated, if slightly alarmed. He glanced down at his wand, which stuck out of his pocket.

The boy seemed to take note of this. "I wouldn't try it. You won't get anywhere." His voice was of the upmost certainty.

John frowned slightly, struggling to work him out. "I'm sorry, I... what's your name?"

"Sherlock Holmes."

"So, you... familiar with Hogwarts, or..." John quickly registered that the attempt at conversation went nowhere, and muttered irritably, "okay."

"Do you know about the houses?" Holmes asked suddenly.

"No. Or, I've looked at some of our books, so I know of them, but..."

He still didn't look up, obviously only half paying attention. "So which do you want..." he paused, frowning at the book in his hands before continuing, "to be in?"

John shrugged. "I don't know," he said, honestly. "Preferably not Slytherin, judging by the history books."

"Oh, you won't be in Slytherin. No, no." One corner of his mouth quirked up, though the overall expression this gave was impossible to decipher. He unzipped his bag and lifted something out; something smooth whose tongue bobbed out as he watched.

John blinked, surprised, although nothing could shock him anymore. The snake slid through his hands calmly, tongue flicking and emitting a low, fluxuating series of hisses as it coiled around his arm. "I, however," he said, without looking up, "Will be."

A cringing sensation went through John's chest, realising the mistake. "Look, I didn't mean- I-"

But Sherlock no longer seemed to be listening. John watched slightly uncomfortably as he lifted the snake close to his face; the snake seemed too alert for his liking. It emitted a second bout of hisses; he was doubly surprised, however, when the other returned the sound with equal ease.

For some time, he presumed that this was a mere affection, in the same vein as someone would a dog. Yet there was something unnerving about it which he struggled to describe. As hard as he tried to mind his own business, he once caught Sherlock watching him out of the corner of his eyes as he hissed; a second time, he turned his head as John looked over and fell silent, though the snake's dark eyes remained fixed upon him.

The idea that the two were genuinely communicating was one that John first dismissed as madness, and yet, yet...

It wasn't exactly the innateness of the sound Sherlock made, or the subtleties of his expression that spoke of converse. It wasn't even exactly the thought that in this strange new world, it was possible to converse with a snake. It wasn't exactly any of it.

But something about it made his skin crawl.

Just then, the door swung open and a ginger haired boy looked into the compartment, followed by another boy with messy hair and round glasses.

"Sorry, mind if we join you? Someone set off a smoke bomb down there," he gestured vaguely down the train.

"Uh, yeah, sure," said John immediately, moving over to make room. Sherlock said nothing, but fell silent abruptly, scanning the newcomers. The snake seemed somewhat wary; it wrapped more tightly around his arm, partially disappearing into his sleeve.

The ginger-haired boy stared at Sherlock, agape, then quickly sat down next to John. His friend joined him with a curious glance at the snake. He placed a cage on the table between them, containing a large white snowy owl who ruffled her feathers irritably, and dumped an array of sweets onto the seat. John watched the two new pets, remembering the cat he'd wanted to buy, before also remembering that he should probably try to make friends.

"I'm John, by the way," he added belatedly.

"Ron," introduced the red-headed boy, beaming. "And Harry Potter," he said, expectantly with a gesture to his friend. John stared at him blankly.

"He's muggle born," said Sherlock, unexpectedly.

"Oh," said Ron. John got the impression that there was some distrust towards Sherlock there, though they didn't seem familiar with each other. "Never mind."

John blinked, confused. "You're magic, too, then? I mean, not- I mean, you're from a magic family?"

"Yeah. All my brothers have been here." He sounded gloomy. "Harry's family are muggles too, though."

"Oh," he said, trying and failing to think of something more interesting to say.

The last of the journey passed fairly uneventfully. Ron and Harry, who seemed fast friends, chatted amongst themselves; John occasionally joined in the conversation, while Sherlock sat in silence, seeming to have bored of their company.

By the end of the journey, John held several chocolate frog cards, gifted to him by Harry, who seemed equally as fascinated as he was, and had watched Ron try several times to turn his rat yellow, an apparently impossible feat.

As train rolled to a standstill John gathered up his belongings, checking around him to make sure he left nothing behind. A small piece of glass glinted at him from under Sherlock's side of the table. He reached down and held it over his hand. It had two strips of plastic either side of the glass, and magnified the pattern of his skin hugely. He frowned, turning to look for Sherlock; however, he had disappeared the moment the train slowed, and was nowhere to be seen.

Then he caught sight of the castle towering above them, and the glass slipped into his pocket, forgotten.

John couldn't remember feeling this nervous since Harry had told him she'd convinced their headmaster he had stolen the door of the girl's bathroom.

He watched as a Moriarty, James was sorted into Ravenclaw and walked off, giggling oddly. Sherlock, after a long pause, was indeed sorted into Slytherin.

John watched Holmes go with a slither of gratitude and a bout of relief that somewhat calmed his nerves. At least that was one person he wouldn't have to share his house with. Supposing Sherlock was correct, in any case. His adverted his eyes from the crowd modestly, shuffling his feet. He couldn't help feeling a slight discomfort towards the Slytherin table; the upturned faces all seemed to have the somewhat bored arrogance Sherlock's had during the train journey.

He supposed that it was his good fortune that he knew virtually nothing about the houses; at least this way he lacked the added anxiety of worrying which house he would be allocated to.

He was one of the last to be called, and stumbled forward somewhat ungracefully before jabbing the hat onto his head. He flushed, realising he must have looked a fool. He consoled himself with the thought of the boy who had forgotten to remove the hat upon leaving the stage.

The hat promptly shouted, "Gryffindor," and John took his place at the red and gold table to thunderous applause; luckily so, as he had been thoroughly confused as to which table was which. He was joined by his sister, then Ron, and the sorting ceremony ended, promptly followed by the largest school dinner John had ever come across.

"First years, hurry yourselves up," called a dark haired boy, whom John judged to be somewhere around his fifth year. "Some of us want to sleep."

"Who's he?" John asked, to nobody in particular.

"Greg," answered a ginger haired boy, who seemed to be Ron's brother. He didn't bother to lower his voice. "He's Quidditch Captain now, but the hat tried to put him in Hufflepuff."

"Oi, watch your mouth," he replied evenly.

Before long, Greg's wish was granted and people started to filter out of the hall; another ginger haired boy led the way out (John wondered exactly how many brothers Ron had), and the group squeezed through the door in unison with Slytherin. Catching sight of Sherlock, John chased after him, catching up just outside a dim looking corridor.

"Hey," he panted.

Sherlock held out his hand silently.

"Uh," said John. Frowning, he shoved his hand into his pocket and handed the glass piece to Sherlock. He noticed slightly uncomfortably that an older boy had stopped and was watching them, eyebrows slightly raised. "Well, I better, er-"

The older boy's lips upturned tightly. "Better what? Catch up with them?"

John spun around, staring at the empty hall.

"Come, Sherlock."

"Wait, I-" John started, but they disappeared around the corner and were gone.

"Great," he muttered. "Just... great."

He jogged slowly in the direction they had been going, limping and cursing Harry for forgetting him. He reached a long winding staircase, which he presumed they must have followed. He came to a dead end and turned back; he found a side alley and entered a long corridor, with far too many offshoots and dead ends to navigate; and eventually came to a kind of staircase bridge between two walls, pocketed with various entrances and openings. He flopped down, defeated. He was more than a little annoyed at being left behind, and even more so at not being missed.

"Never did catch up, then."

John looked up to be met by Sherlock's unapologetic stare. He let out a huff of disbelief. "You bloody-"

"Yes, well, it was a 'shame' to stop there," he said, an odd enthusiasm in his voice.

He stared at him blankly.

"It's just around the corner," Sherlock said, humour making his voice quaver. "It's just around the corner, and you-"

John stood abruptly. The sudden change made stars burst in his head, but he gave no outward sign of it. "I'm glad you," he snapped, "find it so funny." He spun around, not really caring why the Slytherin was out of bed so late, and not really caring how their paths had ended up crossing in such a maze of corridors. He turned the corner. There were no lights on; but he supposed it was night-time, so that was a given. He reached the door and yanked on the handle aggressively, but it was locked. "Oh, great," he muttered, for the second time that night.

"Here," said Sherlock, appearing noiselessly at his side. "Alohomora."

The door unlocked with a satisfying click. John put his hand on the handle, but didn't turn it. He looked at Sherlock, lips pursed, opened his mouth to make some kind of angry retort, then closed it again. He opened the door and stepped inside, slamming it on Sherlock, who immediately opened it again, some kind of manic excitement in his eyes.

Which John did not share.

At all.

Because at his feet, there lay three giant mouths. Towering above there hovered the three giant heads to which the mouths belonged. And there lay, beyond them, one giant body to which all three belonged.