A great man once said that practice was the sole criterion for testing magic.
"No casting magic in the corridors!" Filch's aged face was stern, and a cat with scruffy fur sat at his feet.
"But, Mr. Caretaker, we're in a classroom," the girl said quietly. "We haven't broken any school rules."
"That's still not allowed!" Filch said loudly.
In an empty classroom on the castle's first floor, training dummies lay scattered in a jumbled heap.
With his hands on his hips, Filch glowered at the two young wizards before him.
"Mr. Filch, we have a permission slip written by Professor McGonagall." One of the boys calmly put away his wand and pulled a small square of paper from his pocket.
Filch took the slip, looking suspicious, but Professor McGonagall's sweeping signature on it could not be faked.
As Hogwarts Castle's lifelong caretaker, he had seen generation after generation of students leave and was naturally very familiar with the professors' signatures.
Oh, except for the Professor of Defense Against the Dark Arts, who changed every year.
Filch read the slip over several times, picking at the signature with his slightly grimy fingers. There had been a case like this two years ago-
Filch regarded it as a lifelong humiliation, a stain on his career.
Those damned Weasley brothers from Gryffindor had been caught by him wandering around at night in their first year, but they had produced a slip bearing a professor's signature, proving that their nighttime excursion was to assist the professor with magical research.
He had assumed that first-year wizards were unlikely to lie.
But reality had proved him far too naive. In hindsight, the twins' story had been full of holes. He had even gone out of his way to ask the professor in question about it, but the professor's bewildered expression had said it all.
The two young wizards cornered in the classroom by Filch were, of course, Su Er and Hermione.
The slip was genuine, too.
"I'll confirm this with Professor McGonagall." Filch picked at the writing a few times but failed to scrape it off.
So he coldly delivered that parting remark and left the classroom with his cat.
A little while later, Su Er and Hermione left the classroom as well.
"If only there were somewhere we could practice magic without being disturbed," Hermione said before parting with Su Er at the stairs.
Her words stirred something in Su Er, and dormant memories suddenly came rushing back.
There seemed to be just such a place in Hogwarts Castle: a mysterious room that could take countless forms. Whenever a young wizard needed something, it would answer.
Wasn't it on-the castle's seventh floor?
Maybe I could explore it tomorrow when I don't have any classes...
The next day, after Herbology, Su Er wandered up to the castle's seventh floor. All he remembered was that the room was near a picture of trolls holding clubs. How to get inside still required investigation.
The corridors on the castle's seventh floor were enormous. Su Er searched half of them without finding the picture that marked the entrance to the Room of Requirement.
It was taking rather a lot of time, and dusk was falling. He had to end his search and leave the seventh floor for dinner in the Great Hall. If he was late, he would have nothing but bread to chew on, and that simply would not do.
There was no urgent need to find the Room of Requirement. He could search the remaining half of the corridors tomorrow.
Preoccupied with his thoughts, Su Er failed to notice the person coming toward him on the stairs.
"Oh, are... are you all... all right?"
"I'm fine, Professor Quirrell." Su Er brushed the dust off his wizard robes and nimbly got up from the floor.
Quirinus Quirrell-no, he had already been molded into Tom's image. To be precise, he ought to be called Voldemort Quirinus Quirrell.
Quirrell kindly asked what Su Er was doing there, puzzlement and curiosity flickering in his eyes. Under normal circumstances, young wizards did not visit the castle's upper floors.
"I didn't have any classes this afternoon, so I thought I'd look around the castle." Su Er kept his head down, avoiding Quirrell's eyes.
If he remembered correctly, Voldemort was one of the few wizards in the original story skilled at Legilimency. The best way to deal with magic like that was to avoid eye contact.
"Oh?" Quirrell looked at Su Er, who stood with his head lowered in his Hufflepuff robes, and some of the puzzlement faded from his eyes.
"In... indeed... Hog... Hogwarts Castle is... a... a truly... wonderful... place. When I was young... I did the same... same thing."
Quirrell stammered through a few exchanges with Su Er, asked how his studies were going, and then let him leave.
Their conversation was a perfect display of harmony between teacher and student.
But Quirrell did not notice Su Er glance back at him after descending a few steps.
Was Voldemort heading to the Room of Requirement?
What was he going there for?
With those questions in mind, Su Er returned to the Great Hall.
If that was the case, I might need to be even more careful while searching for the Room of Requirement. Running into Quirrell once or twice would be fine, but if it happened too often, Voldemort would inevitably grow suspicious. That wouldn't do...
Since Voldemort could possess an adult wizard, possessing a young one would be even easier. For the sake of his life and a happy future, caution was the best policy.
Having quickly decided to make another trip tomorrow, Su Er cheerfully picked up his silver dinner knife. Tonight's dinner was charcoal-grilled steak. If he ate fast enough, he might even get a second serving.
That evening, Morn and Justin, both terrible chess players, began another heated showdown at wizard's chess, while Su Er held a copy of An Introduction to Transfiguration and read with keen interest.
Even terrible chess players had different levels of skill. Morn, who came from a wizarding family, was clearly a cut above Justin.
But there were always surprises.
"You lost!" Justin whooped, jumping out of his seat with a smug expression.
Su Er turned his head for a look. Several pieces lay beside the board, and a black knight was brandishing its sword as it drove the white king off his throne. The white pieces that had been eliminated earlier were swearing at Morn.
Morn conceded defeat, looking dejected. According to their agreement, tonight's loser had to go to the Hogwarts Kitchens to fetch late-night snacks.
"Bring me some too. Thanks!" Su Er called with a smile at Morn's despondent retreating figure.
Without turning around, Morn raised a hand and waved.
"What are you reading?" Still flushed from his victory, Justin leaned over beside Su Er. "An Introduction to Transfiguration?"
Justin recognized every word on the page, but why did they suddenly become incomprehensible when put together?
"This is fourth-year Transfiguration material." Su Er amiably answered Justin's question and explained what a Switching Spell was.
But judging by the spirals in Justin's eyes, he had not understood a thing.
"The Sorting Hat must have made a mistake. You should've gone to Ravenclaw, not Hufflepuff." Justin looked at Su Er as though he were a monster.
A little while later, Morn returned to the Hufflepuff common room with his arms full of food.
After eating his fill, Su Er rubbed his stomach and lay blissfully on his cloud-soft bed, drifting off to sleep.
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