Early on the morning of September 1st, Sherlock packed his things and boarded a train from a station in Surrey bound for London.
His home wasn't far from central London; the journey took only thirty minutes before he arrived at King's Cross Station.
Ticket in hand—given to him by Professor McGonagall—Sherlock easily located the wall between Platforms Nine and Ten.
A number of clearly unusual people were already gathered there.
Children wheeling trolleys, most with an owl perched on top, and adults dressed in outlandish outfits.
They wore dark robes; some even sported pointed hats seen only in drama clubs, drawing plenty of stares from passers-by.
"I told you, Stacey, to stash that blasted hat once we reached the Muggle station! Those Muggles just think your 'pretty' hat looks ridiculous!"
Beside the pointed-hat witch, her husband—dress shirt above, beach shorts below—muttered at her under his breath.
Grumbling, the witch pulled the hat from her head.
"Why do I get the feeling everyone's staring at you?"
"Nonsense! My outfit's exactly what Muggles call normal, isn't it, Gareth?"
At his father's question, the fifth-year Hogwarts student covered his face, wishing the ground would swallow him.
He'd warned his parents at home, yet here they were.
Sherlock almost laughed at the family's antics, but professional training kept his face straight.
To avoid notice, the wizarding parents didn't cluster in one spot.
Instead, they strolled casually about the station, waiting to slip through the magical wall one by one.
No matter how odd their clothes, the moment they passed into Platform Nine and Three-Quarters, the watching Muggles forgot them.
It was as if the incident had never happened.
Such was the effect of the Muggle-Repelling Charm; wizards used it whenever large gatherings risked exposure.
Parents with children entered Platform Nine and Three-Quarters in orderly fashion, and soon it was Sherlock's turn.
He carried only a single suitcase.
The owl he'd bought for post had flown to Hogwarts on its own the day before.
Suitcase in hand, he eyed the unremarkable wall, exhaled softly, then jogged forward.
When his nose was ten centimetres from the bricks, he instinctively shut his eyes without slowing.
An instant later he felt himself pass through—yet it was as if nothing had happened.
But the sounds around him had changed.
Owls hooted, cats mewed, even mice squeaked.
Parents chattered, giving last-minute warnings to their children.
Sherlock opened his eyes.
Steam from the locomotive drifted over the bustling crowd; cats of every colour darted between legs; wizards in modern or medieval robes bade their children farewell.
At the sight of this world so unlike ordinary society, Sherlock's mouth curved into a smile.
He shrugged, lifted his suitcase, and boarded the Hogwarts Express alone.
Empty compartments dotted the front, yet he kept walking until he reached the very last carriage and settled into a private compartment.
The journey to Hogwarts would take the better part of a day.
He used the time to pull a quill and parchment from his trunk, set them on the table, then lean back with eyes closed in thought.
Sherlock strained to recall the plot of the original books—he hadn't retained much.
Apart from the first novel, which he'd read in English, the remaining six he knew only from short movie-recap videos.
That left his knowledge of the storyline woefully patchy.
The final outcome was something he remembered.
Good triumphed over evil; the Boy Who Lived defeated the Dark Lord Voldemort.
But the particulars of each book had grown hazy.
When the train lurched into motion, he opened his eyes and wrote two words on the parchment.
"Chamber of Secrets," "Basilisk."
Those were his only solid memories of the second book.
A hidden chamber within Hogwarts had opened, releasing a giant serpent—the Basilisk—that attacked students throughout the year.
Yet no one at the castle had died, and the plot somehow tied back to You-Know-Who.
Beyond that, he could recall nothing.
Unable to dredge up more, he drew his wand and tapped the parchment.
The note shredded into confetti.
The Severing Charm: a fairly advanced basic spell, and one he had already mastered.
He slid the window open and tossed the scraps outside—then gaped as a Ford Anglia soared past above the train!
Inside the flying car, he could clearly see Harry and Ron's gleeful faces.
Harry spotted him too and waved excitedly.
Sherlock's eyes widened as he remembered: the flying car to school was part of canon.
He squinted at the shrinking dot above and chuckled.
"Man, kids really know how to have fun."
Then he muttered,
"They did make it safely… right?"
Harry and Ron, meanwhile, were having the time of their lives.
"I just saw Professor Cavendish on the train!" Harry exclaimed.
Ron, hands on the wheel like an old hand, whistled in delight.
"He'll be impressed now!"
"Not just him—everyone at Hogwarts will be!"