In Charm Class, Professor Flitwick spent ten minutes going over the key points of a few charms, and then let everyone start practicing.
Soon the classroom was filled with the sound of incantations, interspersed with noisy chatter, making it very lively.
Most people were chatting while casually waving their wands, and Professor Flitwick didn't intervene much, only going over to correct anyone who made a mistake.
But halfway through the lesson, a milky white head suddenly poked through the wall from the outside.
"Sorry, Filius, for interrupting your class," said the Hufflepuff ghost Fat Friar. "But the Headmaster needs to see Kael for something, could you let him go to the Headmaster's Office now?"
The classroom fell silent in an instant, everyone curiously looking at Kael.
"Of course, no problem."
Professor Flitwick, who was correcting Ryan's gesture, immediately said, "Quickly go, these simple charms surely won't be too difficult for you, right?"
Kael nodded, stood up and left the classroom, heading into the corridor outside.
"Friar, why does the Headmaster want me?" he asked the ghost beside him.
"I don't know," Fat Friar shook his head and said, "I ran into Albus in the entrance hall, he was seeing off the Ministry of Magic people, didn't say why, just asked me to call you over."
"Thank you," Kael said.
"You're welcome," the Fat Friar said, then disappeared like he'd just dive-bombed through the ground.
Kael made his way to the eighth floor.
The door to the Headmaster's Office was open, so he didn't need a password and went straight inside.
The Ministry of Magic people had already left, and Dumbledore was seated behind the desk, with the portraits of previous headmasters snoring in their frames.
Just as Conna had mentioned, he seemed to have spent the night without sleep, wearing deep fatigue on his face.
"You've arrived, have a seat," Dumbledore pointed to a chair in front of him.
"Would you like some tea?"
"No, thank you," Kael shook his head.
"Alright, but I might need some," Dumbledore said, "Getting older, staying up all night really isn't pleasant."
With those words, a steaming cup of red tea appeared on the table, and Dumbledore routinely added a whole dish of sugar cubes to it.
"You must have many questions," he took a sip of the tea, "Just as well, I have a bit of time now, I should be able to answer some of your puzzles."
"Are you sure you don't need a nap first?" Kael looked at the fatigue on Dumbledore's face, "I'm not really in a hurry."
"No need," Dumbledore said, "In half an hour I still have to go to Grimmauld Place, I'll rest there just the same."
"Alright."
Kael nodded, hesitating about where to start asking questions, but Dumbledore spoke first.
"We'll start with the Room of Requirement... That's right, just as you'd imagine, I blocked the exit and placed a platter that connects to the kitchen inside."
"When did this happen," Kael asked, puzzled, "I don't have any impression of it."
"I've only been there once," Dumbledore said, "When you were paying close attention in class, I did all that by the way."
"How is this achieved?" Kael asked, "It's the first time I know, the Room of Requirement can actively close."
"It's a little privilege of the Headmaster," Dumbledore said, "Coincidentally, I found a most original Hogwarts map in the library at the time, which marked the location of the Room of Requirement, and its usage method.
The Headmaster could alter the way the castle's magic power is allocated, shifting the magic on that wall to another area, and without magic power, the door naturally wouldn't appear.
Kael suddenly understood.
No wonder, the whole Room of Requirement relies on the power operational dynamics of Hogwarts Castle... If we think of all Hogwarts as a painting, Dumbledore's method is equivalent to using a knife to directly cut out the part of the door.
In this way, Kael having a key would be useless.
"Speaking of this, I have a question myself," Dumbledore raised his head, "How did you get out? I just checked a moment ago, that place is still without magic power."
"Because the memory of Rowena Ravenclaw ended," Kael said, "The Room of Requirement was constructed based on her memory, so naturally it vanished after the memory ended."
Just like when Dumbledore inadvertently discovered the Hogwarts map, Kael leaving the Room of Requirement was similarly coincidental.
Because without demand, theoretically the Room of Requirement does not exist, and after the room dissolved, Kael, as an extra person, naturally got kicked out.
This is a rule of the Room of Requirement itself, unrelated to whether a door exists or not.
"Does this situation exist?"
After hearing Kael's explanation, Dumbledore paused for a moment, evidently it was the first time he'd heard of it.
"Rowena Ravenclaw mentioned it briefly to me the first time she took me," Kael explained, "I asked her how long the memory would last, she didn't say, just told me I could stay inside without worries, when the memory fades, the Room of Requirement would send me out."
Dumbledore's hand holding the tea practically paused, and he smiled wryly.
"Quite the coincidence, seems I went overboard."
"Could you tell me why?" Kael couldn't help but be curious, "Going through all that trouble just to trap me in the Room of Requirement? I can't see the point of doing this."
"To ensure you couldn't participate in last night's events," Dumbledore softly said, "About ten days ago, Phineas told me Malfoy had moved the Vanishing Cabinet out of the common room, and I knew their plan would soon commence.