After Sherlock finished explaining his deductions in one breath, both Harry and Ron sat there utterly dumbfounded.
A moment later, it was Harry—who'd already witnessed Sherlock's talents—who recovered first.
"That was brilliant!
Sherlock, you're absolutely amazing!
Now that you've explained it, everything seems so obvious."
"I knew you'd say that, dear Harry," Sherlock replied with a small shrug. Then he turned to Ron, offering sincere advice:
"If possible, you should really consider getting a new wand. Using secondhand books and robes is fine, but a wand is something deeply personal—if it doesn't match you, it could affect your spellcasting."
Ron flushed a little. "It's all right. It may be old, but it still works pretty well for me."
Sherlock understood.
No money.
Impressed by Sherlock's brilliance, Harry and Ron quickly shifted the conversation and earnestly began asking him questions.
That was when they learned that Sherlock referred to his method as "deductive reasoning."
It was a technique that combined observation, analysis, and logical inference.
By keenly noticing small details and applying knowledge and logical principles, one could draw conclusions about people, events, and even hidden truths.
According to Sherlock, anyone could master it with practice, provided they trained their powers of observation and gained enough knowledge. But Harry and Ron just shook their heads vigorously.
Yeah, right. That kind of thing was clearly a talent—you couldn't just learn it!
Still, it didn't stop the trio from diving into a lively discussion.
Just as the atmosphere hit its stride, there came a knock at the compartment door.
Two young wizards stood outside.
And, as it happened, Sherlock recognized them both.
One was a round-faced boy—the very same one Sherlock had observed while waiting on the platform earlier. At the time, Sherlock had deduced: New student, parents absent for unknown reasons, raised by grandmother, forgetful, timid, and lacking in confidence.
But now, seeing the boy's tear-streaked face, even Harry and Ron could tell—no deduction necessary—that he was both sad and upset.
The other was a girl with bushy brown hair, slightly prominent front teeth, and an air of self-importance.
Hermione Granger.
Sherlock had first seen her in front of the Leaky Cauldron before term began.
Unlike the three boys, Hermione had already changed into her Hogwarts robes.
"Has anyone seen a toad? Neville's lost one," she said sharply.
It wasn't just what she said—it was the way she said it. Her tone and expression gave off an unmistakable air of superiority.
Harry didn't react much, but Ron immediately frowned.
Then, Hermione heard a familiar voice:
"We haven't seen a toad, Miss Granger."
Harry and Ron both turned to stare at Sherlock in surprise.
"Wait a sec—how'd you know her name?" Ron asked. "She's not even carrying a suitcase!"
He tried imitating Sherlock, examining Hermione closely for clues that might give away her identity.
Unsurprisingly, it was no use.
Sherlock shook his head. "We've met before."
Ah. So they already knew each other.
Harry and Ron both exhaled in relief.
For a moment there, they'd honestly thought Sherlock had somehow deduced Hermione's name on the spot again—like magic.
Hermione, too, seemed surprised to see Sherlock again.
Unlike Harry and Ron, she was naturally outgoing. But her first encounter with Sherlock had left such an impression that she'd been a bit shy at the time.
Now, with that moment a month behind her, she had fully returned to her usual self. She beamed and exclaimed:
"Holmes! What are you doing here?"
Without hesitation, she plopped down in the empty seat next to Sherlock.
It wasn't just Harry and Ron—Sherlock himself looked a bit taken aback.
Are we really that familiar with each other? he wondered. We've only met once.
But this was just the beginning.
What followed gave the boys a firsthand look at what it meant to be an unstoppable social force.
"Oh, right—I'd meant to ring you, but I got so busy I forgot! Did you finish all the textbooks?"
Sherlock nodded. "I did."
"I knew it!" Hermione's eyes lit up. Then she launched into a stream of rapid-fire chatter:
"Have you tried any spells yet? I practiced a few simple ones at home, just for fun—and they actually worked!
Also, I forgot to tell you—no one in my family has magic, so I was so shocked when my Hogwarts letter arrived! But thrilled too—this school is supposed to be the very best!
I've memorized all the textbooks already, of course. Though I do hope that comes in handy…"
Once she started, she didn't stop.
Just like with Neville, even without Sherlock's analysis, Harry and Ron had already formed a pretty clear impression of what kind of girl she was.
Whatever House I'm sorted into, Ron thought grimly, please don't let it be hers.
Unfortunately for Ron, Hermione had now noticed the wand still clutched in his hand.
"Oh? Were you doing magic just now?" she asked brightly. "Go on then—let's see!"
Ron immediately panicked.
His earlier spell hadn't worked—and it was bad enough to embarrass himself in front of Sherlock and Harry, whom he already considered mates.
But in front of Granger and Longbottom?
He glanced at Neville's still-teary face… then at Hermione's eager, expectant gaze.
Subconsciously, he turned to Sherlock for help.
Harry, too, looked toward Sherlock with quiet desperation.
Help us, please, oh mighty genius.
Sherlock got the message.
"Ron's wand isn't quite right for him," he said smoothly. "Allow me."
He drew his wand, pointed it at Harry's taped-up glasses, and flicked his wrist.
"Reparo."
A soft, shimmering sound filled the air—and right before everyone's eyes, Harry's cracked and taped-up glasses were instantly restored to their original, pristine state.
Harry stared in shock.
He took off the glasses, examining them closely.
Ron leaned in for a better look—and the two of them realized they really had been restored to like-new condition, fresh from the shop.
Even Hermione was visibly impressed.
The Mending Charm—Reparo—restores damaged objects to their original form.
Hermione could cast it too. But what surprised her was how fluent Sherlock's spellcasting had been—far more polished than her own.
Add to that the time he'd instantly deduced her parents were dentists when they first met…
Suddenly, for the first time in her life, the self-proclaimed top student felt… threatened.
She cleared her throat, just about to comment on Sherlock's performance, when her eyes caught sight of Harry's forehead—now fully visible without the glasses.
Her eyes widened.
"You're Harry Potter? The one who defeated You-Know-Who?!"
Harry blinked, then quickly said, "That's me—er, I mean yes, but Voldemort didn't really die. He's… still alive, in a way…"
Sherlock frowned. This was new territory for him.
"Harry, you said Voldemort is still alive?"
"Yeah. Hagrid told me. He's too weak to do anything now, but he might not be gone for good."
And just like that, Sherlock, Harry, and Hermione launched into an open, animated discussion about Voldemort—completely oblivious to the effect it was having on Ron and Neville, who sat nearby, pale-faced and trembling.