From Azkaban to Hogwarts.

“Something very unpleasant happened yesterday, and this morning you were wandering around the castle wearing an invisibility cloak—I think I need an explanation, Mr. Potter.”

William used magic to restore the gathered pieces of paper to their original state and walked over with a stack of parchment.

"Professor—I heard a strange noise, like someone was very angry. His voice woke me up. I came out of the lounge and have been looking for it. The sound is intermittent, but I can't find out who made it."

"sound?"

"Yes, Professor—it's ringing again!"

Harry suddenly raised his voice and pointed to one side of the wall, saying, "Over there, right there!"

"Petrify them all!"

William's spell followed immediately, but to no avail—the wall that was struck made a sound, but it quickly disappeared.

"It's gone, the voice is gone."

Harry shook his head, giving William the illusion that he was listening to a ghost story.

"who?"

The searchlight came on, and Mr. Filch appeared.

Chapter 130 A New Breakthrough

“Oh, Professor William, Professor Adams,” Filch glanced uncertainly at the sky, but finally said the rest of the sentence, “Good morning.”

"what--"

Filch spotted a third figure, and his earlier disappointment vanished, replaced by renewed fighting spirit. "Professor, have you caught a student who broke the rules?"

"That's the theory. Professor Adams and I are discussing who should put him in solitary confinement."

William responded with a smile—the experiment to capture that so-called voice had just failed, but he didn't think Harry was lying. It was best to keep the person with them; if they sent him to Mr. Filch, the subsequent investigation would not be able to continue.

“It’s time to put them in more solitary confinement. It’s one thing to wander around the castle in the middle of the night instead of sleeping, but to use magic in the castle so early in the morning—” Filch seemed to have lost all sleepiness when he talked about this, but after realizing that it seemed to be a bit of a dig at the professor, he immediately ended the conversation and made an excuse to go on patrol elsewhere.

“Filch is quite conscientious, but I doubt the students will like what he’s doing.”

Adams shrugged as he watched Filch's retreating figure.

"He's the castle caretaker. The students' liking him is what caused the trouble. Just think about the students who were put in solitary confinement this time. If they liked Filch, the school would be in complete chaos."

“That’s true.” Adams nodded, recalling the students who had been sent to his place for solitary confinement. “But speaking of which, do you think Professor Snape or Filch was less popular?”

"It shouldn't be Professor Snape, at least the Slytherin people like him quite a bit."

"I think it's Snape. At least every house has someone who doesn't dislike Filch."

The unexpected interruption startled the two, who were habitually joking, and they exchanged a glance before looking behind them—the person who had just interrupted was right there, a genuine student, a Gryffindor, a second-year student.

'Why would you joke like that!'

'You didn't notice either?'

The two exchanged accusatory glances—there was no way around it, it was just past four o'clock, and it was the weekend. Even Adams, who had work to do, had only gotten up early to trick William. The two, so sleepy, had forgotten that there was a student next to them.

“It is wrong to speak ill of the professor, and there will be no punishment this time. However, if I hear any more bad things about the professor in the castle, I guarantee I can put you in solitary confinement for six months, Mr. Potter.”

"I closed it again after six months. The greenhouse was full of plants that needed care, and also full of dragon manure that needed composting."

The two professors shamelessly used threats against the students—and it was very effective.

"May I leave now, Professor?"

"I'm afraid that won't work. I'm quite curious about that mysterious voice you mentioned. Could you tell me more about it?"

“Yes, I first heard that voice when I was in solitary confinement with Professor Lockhart, and this is the second time I've heard it while I was sleeping—it's a terrifying voice. Cold and murderous, it's saying, ‘Tear you apart…kill you…’”

"Human voice?"

William was taken aback—he thought it was some strange noise, like the occasional sound of a glass ball rolling in a building, but it turned out to be a human voice?

"Yes, it should be a human voice—a chilling, breathless, cold and vicious voice."

It's strange—William can accept any strange sound, but what's with the human voice?

"Adams?"

William asked a rather succinct question, only to be met with Adams's gaze—'You're the professor of self-defense magic.'

"I've never heard of such a thing. It's fine if it's the sound of an animal, but as for humans, I don't think I've ever heard of a precedent. Maybe I can look it up—but don't get your hopes up too high."

William answered quite frankly, but since there were experts at the school, he wouldn't just brush off the student like that. "You can ask Professor Lockhart. He's very knowledgeable and knows much more than I do. He should be able to give you the answer."

William thought Harry's face suddenly froze, perhaps because of the dim lighting.

"Alright, I'll let you off the hook tonight. Don't brag, or you'll get at least three times the usual solitary confinement. Go back and get some sleep. I'll investigate that voice thing thoroughly."

Harry donned the Invisibility Cloak, bid farewell to the two professors, and hurriedly left.

Judging that he had mostly left, Adams asked, "Is nobody here?"

"That's all, I think."

William yawned and used his wand to survey his surroundings.

"Dumbledore really spoils this kid—the Invisibility Cloak was given to him by the Headmaster, wasn't it?"

"I suppose so. The loss of the Invisibility Cloak is a price no child can afford. Besides, the Invisibility Cloak is nothing—the school even changed its schedule specifically because Harry is enrolling."

"Revise?"

"Of course—otherwise, why would there be four deans in that grade? How many grades do you think Professor McGonagall could be in charge of while managing school affairs?"

"That's true. Four heads of house teaching the same grade at the same time, that's quite a lineup. How are Harry's grades?"

"It wasn't as good as I imagined. I thought he'd get top marks in every subject, but it turns out the top spot went to his friend—I always thought he was a genius before he enrolled. Speaking of which, William, do you really think that so-called voice wasn't something he made up on the spot to escape solitary confinement?"

"It shouldn't be. The story is too far-fetched. I suspect he's been cursed."

"curse?"

"Yeah, he hears sounds that others can't hear, and then he's paranoid all the time. Otherwise, why can't others hear those sounds? Is there some kind of ghost specifically trying to scare him? What kind of ghost could be invisible to both of us, but only to a second-grader?"

"But what kind of curse is that? I've never heard of it—William, William?"

Adams nudged the stunned William, only to find a look of delight on the other's face.

"Yes, ghosts! Hogwarts has ghosts!"

"Even a ghost couldn't scare us like that, not even Pikachu!"

But William wasn't referring to Harry's curse—he was thinking about the two chickens that had died tragically.

In the magical world beyond reasoning, he encountered a problem, but now he discovered that the other side was on his side—the ghosts wandering Hogwarts knew just as much as the paintings, and if he asked them carefully, he could probably find a new breakthrough.

“William!”

Adams's shout brought him back to his senses.

"what happened?"

"Harry's curse?"

"Report it to the headmaster. Surely Dumbledore can't handle this, right? Whether it's a curse or a concussion, it should be fine."

"'Concussion,' what kind of strange pronunciation is that?"

In his haste, he blurted out a Chinese phrase... Luckily, Adams didn't understand—William was a little embarrassed.

His main concern was that he suspected Harry had suffered some aftereffects from hitting a tree at school.

"Nothing, it's a Muggle word, a kind of illness."

Chapter 131 Searching for Ghosts

"Sorry, William, it's getting late, I have to go take care of the plants."

After a brief chat in the corridor, William and Adams hurriedly took their leave—'A batch of biting cabbages from the East is forming heads, and it's the season when water is scarce.'

Adams said this, and he left quickly without waiting for William's reply.

'Biting cabbage?'

William scratched his head, remembering that this was one of the ingredients for the potion Bone Spirit.

Why did I suddenly think of hand-torn cabbage?

Thinking of this, he chuckled and began to plan how to use the biting cabbage—the herbs grown on campus, apart from the particularly precious ones, were all usable by professors who could simply submit a report.

'Potions are more reliable than magic if they don't expire, although theoretically they shouldn't cause such severe injuries, but I think I should still make some.'

Although the application for Life-Giving Elixir is likely to be approved most of the time, people who are capable of brewing potions prefer to make their own for more complex potions, as they are more confident about both the shelf life and the efficacy.

After figuring all this out, William began to ponder the wonderful ideas that had just floated through his mind.

Looking for ghosts.

Not Peeves, those stubborn elves that refuse to leave, but ghosts transformed from wizards, a remnant of Hogwarts' nearly thousand-year history.

Compared to oil paintings, these ghosts can explore far more places. Even the twins might not have explored as many places as the ghosts—ghosts can walk through walls, and most of the ghosts in this castle have been in school longer than Dumbledore!

'I should have realized this sooner—Professor Binns was limiting my thinking too much. Not every ghost works like Professor Binns, confining themselves to the classroom and office every day.'

'Go talk to Professor Binns and ask for a letter of recommendation or something. Those ghosts are all veterans; I'm still an outsider, and they probably won't cooperate if they ask.'

Ghosts are different from oil paintings. Most oil paintings will give professors face, but ghosts are divided by college. For wizards like William who have no formal background, ghosts can ignore them if they want to—William learned this the first night of school.

'Everyone else goes ghost hunting at night to test their courage, am I going ghost hunting at dawn?'

'Wait a minute,' William suddenly realized something was wrong. He looked at the completely dark windows and remembered Adams running away not long ago—'I really want to curse!'

-

In the brightly lit office, William knocked on the door, using the candlelight filtering through the crack.

"Please come in."

Professor Binns' voice came from inside, and William pushed open the office door.

So many books—

Despite having visited several times, William still uttered the same exclamation as before—in reality, only a few items were placed outside; the main focus was on the room in the back, which was used as a lounge by the other professors. Perhaps because the ghosts didn't need to rest, Professor Binns used the entire back room to pile up books.