As everyone knows, the Defense Against the Dark Arts class at Hogwarts has been placed under a powerful curse by a mysterious man. Even Dumbledore cannot lift it. Perhaps only vampires or werewolves—who are Dark creatures themselves—can resist it.
After all, werewolves are far too dangerous for young wizards, so vampires have become the safer choice.
The next morning, Professor Sprout, Head of Hufflepuff House, held a class in Herbology. This subject was not one Phineas was particularly familiar with. Although he had read many books, that didn't necessarily mean he understood everything in them. He had taken notes on nearly all of them, but Herbology was one of the few subjects he hadn't added much to.
In the afternoon, there was a Charms class taught by Professor Flitwick, the Head of Ravenclaw House. Besides Transfiguration, this was the class in which Phineas had earned his highest marks.
"So, Mr. Black, what question do you have for me?"
After class, Phineas—as usual—sought out Professor Flitwick, with whom he shared a good rapport.
"Professor, since Ms. Ravenclaw left her own private library behind, did she also leave an office? I came across a biography about her in that library and became quite interested in her life."
Phineas chose to reveal part of the truth to Professor Flitwick—at least his intent.
One reason was that Professor Flitwick had taken him to Ravenclaw's private library and had grown more familiar with some of his actions. Another was that, as the Head of Ravenclaw House and a former student of the same house, Flitwick might know more than most.
Sure enough, after hearing the question, Professor Flitwick fell into thought. After a pause, he replied,
"I really don't know anything about Ms. Ravenclaw's office. There's no clear mention of it in the Hogwarts records."
Phineas frowned and asked again,
"So, are the offices of the other three founders clearly recorded?"
At this, Professor Flitwick smiled in approval.
"Why aren't you in Ravenclaw? You'd be a perfect fit. Well, according to the records, Salazar Slytherin's office is now used by your Head of House. Godric Gryffindor's became the Headmaster's office. As for Helga Hufflepuff's office, it's said to be near the kitchens, though its exact location isn't known."
Then, Professor Flitwick added with a twinkle in his eye,
"By the way, do you know where the kitchens are? Just below the Great Hall, behind the fruit bowl portrait next to the Hufflepuff common room. If you tickle the pear in the painting, it will laugh and turn into a doorknob."
He winked at Phineas mischievously, as if to say don't tell anyone I told you.
Phineas smiled back. Though he was disappointed not to learn anything about Rowena Ravenclaw's office, discovering the kitchen's location wasn't a total loss.
After dinner, he arrived at the corridor on the sixth floor at the time Professor McGonagall had given him.
"Classroom 21… Classroom 21… Classroom 21…"
He muttered the location to himself, but there was no obvious clue. When a room couldn't be found, it was common practice among Hogwarts students to ask the portraits. Phineas did just that. Unfortunately, none of them knew anything about a "Classroom 21"—some even insisted it didn't exist.
It seemed his memory of the castle was accurate. There really was no such classroom—or not one that was normally visible.
But Professor McGonagall wouldn't lie. The answer had to lie in her final words: Gamp's Law of Elemental Transfiguration. That had to be a clue.
At Hogwarts, hidden rooms were often concealed behind portraits, tapestries, or statues.
Phineas searched the entire sixth floor. Eventually, he came across a single painting that violated Gamp's Law—food was being conjured within it.
"So this is it. Now, what should I do? Just like this…? I want to enter Classroom 21?"
As he finished speaking, the witch in the portrait nodded and opened a door within the painting. At the same moment, the painting itself swung open like a real door, revealing a half-height entrance.
"So this really is it."
Phineas smiled to himself. He had been guessing. If this hadn't worked, he would've tried other phrases like "open sesame" or "part left and right."
Beyond the passage was a staircase leading upward. At the top stood a wooden door with a bronze plaque that read: Classroom No. 21.
He opened it and stepped inside. The space looked more like an office than a classroom. There wasn't much furniture—just a few bookshelves and about a dozen chairs, all of different shapes and styles.
"Before Dumbledore's classroom, this used to be the office of the Transfiguration professor," came a voice.
Professor McGonagall emerged from a cubicle and approached him.
"But since it was so inconvenient to reach, it was eventually abandoned. Later, I repurposed it as the meeting room for the Transfiguration Club."
"Mr. Black, you're a bit early—but no matter. As you've noticed, none of these chairs are yours. The club has a rule: each member must conjure their own."
Phineas nodded. "Understood, Professor."
He glanced around but found nothing nearby to Transfigure. So he reached into his robe, pulled out a fruit candy, and pointed his wand at it.
"Switching Spell!"
The candy grew in size and shifted texture under his spell. Within moments, an orange armchair appeared.
He studied it for a moment, then picked up the candy wrapper, transformed it, and created a matching cushion. He placed it on the chair and nodded, satisfied.
"Excellent Switching Spell," said a clear voice behind him.
"Are you the new student Professor McGonagall mentioned? I'm Penelope Clearwater, Ravenclaw. But I don't think I've seen you in class before."
"Phineas Black. You can call me Phineas. I'm a new student in Slytherin. That's probably why you haven't seen me yet."