The atmosphere in the classroom suddenly became tense.

Moody grinned. "Mr. Potter, I thought you always looked down upon the Ministry of Magic."

"You are now a professor at Hogwarts and a former Auror of the Ministry of Magic." Harry tapped the table lightly to emphasize his identity. "These are not things you should ignore."

"This is normal teaching content." Moody emphasized.

Harry refuted him seriously: "I don't think it is normal to teach students to cast the Unforgivable Curses."

Hermione and Ron nodded in agreement.

Although many little lions were eager to try and want to experience it for themselves, the majority of them had brains. Just the few words "Unforgivable Curses" were enough to make them feel scared, especially Neville, who looked resistant.

"I am the professor, Mr. Potter. Five points deducted from Gryffindor." Moody kicked the podium hard. The huge "bang" sound scared all the students.

"Fifty points is fine." Harry reached into the Sorting Hat, "but I can't just sit there and watch you cast the Unforgivable Curse on a student."

Moody's face turned pale and he was extremely serious: "You want to attack the professor?"

"I've beaten up every Defense Against the Dark Arts professor in every year," Harry said calmly.

All the little wizards were caught off guard.

This is the fact.

But is it really appropriate to say such things in front of a professor, especially the new Defense Against the Dark Arts professor, in his first class?

"I haven't heard Professor Dumbledore, or any of the Headmasters or professors, say anything about it," Harry went on. "Perhaps you did get permission, but I think it would be reassuring to hear from Professor Dumbledore and Professor McGonagall."

Moody looked at him and nodded stiffly, "Oh, good."

"Mr. Potter has taught the young wizards a lesson: when you are unsure of the situation, don't rashly agree to requests that seem a bit excessive."

"Five points to Gryffindor."

As he said that, he waved to Harry: "Mr. Potter, please sit down first."

"Then let's continue to talk about dealing with the dark arts in this class."

It was as if nothing had happened. He continued to teach his students, talking about all kinds of knowledge about black magic. His level was not low. He could make people fascinated with just a few sentences, and even the boring magic theories became interesting.

Hermione's features twisted as she listened.

Ron's eyebrows were twisted into knots.

After class, the other students left talking and laughing. They loved Defense Against the Dark Arts so much and couldn't wait to finish the homework assigned by Professor Moody, a paper on the theory of dark magic and how to deal with it.

Harry and the others left in a hurry.

"Professor Moody shouldn't be such a person." Ron frowned and muttered, "He has always been disgusted with the Unforgivable Curses and the Dark Arts. My father said that he is the Auror who is most determined to refuse to use the Dark Arts in the Ministry of Magic. If it weren't for him, there would probably be a bunch of Dark wizards in the Auror's office now."

"How could he promote dark magic so openly and use it like this?"

"They're even going to cast a spell on us!"

Hermione said in a dissatisfied tone: "He is simply teaching dark magic and asking us to write dark magic theory! Moreover, I always feel that he is avoiding Harry and always stays away from Harry. And that incense burned for a whole class!"

She looked at Harry: "Harry, you should also realize something? I always feel that you are worried whether he will attack the students."

Harry nodded but said nothing. He led the way and walked through many twists and turns until he arrived at an abandoned classroom.

Take the Marauder's Map from the Sorting Hat.

"I solemnly declare that I will not do any good."

The structural diagram of Hogwarts Castle was spread out, with thousands of names densely packed on a small map. After scanning an area, Harry showed a look of relief on his face: "Sure enough, he is not Moody."

Ron quickly leaned over, almost sticking his head to the map, and pointed at the name of the Defense Against the Dark Arts office: "Alastor Moody, isn't the professor still in the office?"

"No, look at this." Harry pointed his finger at the name "Moody" and moved it slightly downwards. On the way from the Defense Against the Dark Arts classroom to Dumbledore's office, a name moved slowly.

"Barty Crouch?" Ron exclaimed.

"Director of the Department of International Magical Exchange and Cooperation." Harry tapped his finger on the Marauder's Map. "He appears here, perhaps for the Triwizard Tournament."

“But there are too many doubts.”

Hermione raised her hand and rubbed her nose: "No wonder he has been avoiding you. Did he use Polyjuice Potion?"

Harry nodded. "He was very cautious. I don't know where he got the news from. He knew that I had keen senses. He also avoided Snape at the start-of-term dinner, for fear that we would smell the scent of Polyjuice Potion."

"I even lit incense in the classroom, but he seemed to underestimate me."

The demon hunter's sense of smell is stronger than that of an ordinary person. Not only is this crude concealing technique useless, but the scent of those materials is even more incompatible with the smell of the incense, and is more obviously and abruptly exposed to his nose.

Everyone's polyjuice potion smells different. The potion on "Moody" has a chilly winter smell mixed with a hint of blood.

But in addition to the smell of medicine, he also had the complex smell of multiple materials.

Boomslang skin, powdered bicorn horn, and saltpeter...

"So it was Mr. Crouch who locked up Professor Moody and then pretended to be Professor Moody?" Ron was shocked. "But... but Mr. Crouch couldn't do such a thing. Percy has always admired him."

"If it weren't for what happened to his son, he would be the Minister of Magic now, instead of Fudge..."

He lowered his voice and cursed the last word: "Idiot!"

"He's not a good guy in the absolute sense." Harry shook his head and continued to stare at the name "Barty Crouch".

"Don't forget what Harry said. That night, the leader of the Death Eaters was rescued by Winky." Hermione added for him, "Although the leader of the Death Eaters was not Mr. Crouch, the house-elf who could command Crouch must have a close relationship with Mr. Crouch."

Ron was stunned: "But Mr. Crouch has no family anymore."

"After his son Crouch Jr. was sent to Azkaban, Mrs. Crouch died of illness soon after, and Crouch Jr. did not last long in Azkaban."

Harry remained silent as he watched "Barty Crouch" walk into the headmaster's office and stand opposite Dumbledore's name, seemingly starting a conversation. Fortunately, after the Defense Against the Dark Arts class this afternoon, they only had the astronomy class in the evening, so they had plenty of time to wait.

Crouch stayed in the office for a long time and left after more than half an hour.

Harry then put away the Marauder's Map, and the three of them went to the headmaster's office together. The Sorting Hat skillfully read out the password. It was the first week of school and the statue's password had not yet been changed.

Dumbledore was not surprised by their visit: "Harry, Mr. Weasley and Miss Granger, why did you come just now? I was just communicating with Alastor. If it was earlier, Alastor would be here too, and perhaps we could communicate better."

"I have to admit that this was indeed my oversight. I didn't expect him to be so radical. He was never like that before..."

"Why don't you think that maybe he isn't Professor Moody?" Harry interrupted.

Dumbledore was stunned.

Harry took out the Marauder's Map and pointed out the name "Barty Crouch". "We saw him staying in your office just now, and now he is going to Professor McGonagall."

Dumbledore pushed his glasses and looked at the map. He especially noticed his name on it, which made him look surprised. "It's a very exquisite creation. Harry, you never mentioned it to me. How could it be so rare without saying anything..."

"My father's legacy." Harry said simply.

Dumbledore was stunned, then nodded with a regretful tone, "James? What a pity, I didn't realize that he could achieve such success in alchemy."

"So it's Polyjuice Potion?"

He also noticed the name in the Defense Against the Dark Arts professor's office, the motionless "Alastor Moody".

Harry nodded. "He was very cautious, staying away from me and Professor Snape, and even lit incense in the classroom to cover up the smell of Polyjuice Potion."

"But it didn't escape your nose." Dumbledore tried to reach up, grabbed a vague breath, and pulled it gently.

His name gradually disappeared from the Marauder's Map.

"The Hogwarts contract?" Harry asked.

Dumbledore nodded, not sparing his praise: "What a great idea. It's hard to imagine how they did it. It's a bit troublesome for me to do it."

He loosened his hand, and the name gradually emerged again.

"Harry, no wonder you always find me in time." Dumbledore sighed, "You can't use this thing to monitor me."

"I'm not interested in a hundred-year-old man." Harry shook his head. He emphasized the name "Barty Crouch" several times. "What should we do with him now?"

"He is going to cast the Unforgivable Curse on the students, and I strongly suspect he is related to the Death Eaters."

As he spoke, he paused: "What is the name of Mr. Crouch's son, also Barty Crouch?"

"Yes, Mr. Crouch Jr. inherited his father's name." Dumbledore nodded. "Are you doubting Mr. Crouch Jr.? He is dead."

Harry said calmly, "You also thought Peter was dead once."

Dumbledore shook his head. "No, it's different, Harry. Peter only had a finger left, but Crouch Jr. had a complete body. He was buried outside Azkaban, under the gaze of countless eyes."

"Perhaps the Crouch family has some unknown blood relatives?" Harry frowned. "The leader of the Death Eaters that night was able to command the Crouch family's house-elves."

"You don't suspect that the man is Mr. Crouch?" Dumbledore asked them to sit down, his tone a little surprised.

Harry said expressionlessly, "I may not be as blind as a person over a hundred years old. Even if that person is wearing a robe and a mask, I can still tell if he is not Mr. Crouch."

The smell is not different at all.

"As far as I know, the Crouch family has no such blood relatives." Dumbledore shook his head. He poured drinks for the three young wizards. "Although Scrimgeour was very reluctant, he still searched Mr. Crouch's house because it was you who made the accusation."

"Nothing was gained, even after applying Legilimency and Veritaserum."

Harry frowned and shook his head. "Are all Death Eaters as secretive as their master?"

"Shall we arrest him now?"

Dumbledore nodded, his eyes deep and stern: "Fortunately, Harry, you told me the news in time, I almost agreed to let him use the Imperius Curse on you."

Harry said expressionlessly: "You can suggest that Professor Snape take over. His level of brewing potions seems to have declined a lot, and he can hardly control your condition."

Dumbledore sneered, "I think Mr. Crouch is right. The young wizard should have the firm belief to try to resist the Imperius Curse. I will try to give some advice when Professor Moody comes back."

"Professor Moody never seems to use the Dark Arts?" Harry glanced at Ron, who nodded quickly in agreement.