Two days later, feeling his mood had returned to normal, Sherlock finally returned to class.
He had just arrived in the classroom when, before he could even speak, a large group of sixth-year students began to complain.
"He is forcing us to study werewolves, Professor."
Sherlock tapped his forehead.
"Didn't you tell him that I have already covered everything there is to know about werewolves with you?"
"We did, Professor, but he just insisted. He even said that you don't understand werewolves at all and that he would tell us how to identify a Werewolf and kill it!"
"He also won't let us answer questions. Even when he asks one, he won't let us speak, insisting on tirelessly repeating knowledge we already know by heart!"
"We told him that this is a practical class and that we've basically learned all the theory, but Professor Snape just won't listen!"
"He even assigned us two rolls of Parchment on werewolves! We have to do test papers in our spare time—we don't have time to write this!"
Over the past two days, in all the Defence Against the Dark Arts classes taught by Snape, the students had been complaining incessantly.
He completely ignored the normal teaching schedule. Even in the first-year classes, he insisted on teaching children who had just learned the Levitation Charm how to kill a Werewolf.
If there wasn't something fishy about this, Sherlock would be able to take his own head off and use it as a Golden Snitch.
Combining this with Snape's strange attitude when Sherlock and Lupin went to ask him to substitute teach, it was obvious from these few Defence Against the Dark Arts classes that he was definitely trying to hint at something.
But Sherlock still had to clean up the mess he had made. If he had known this, he might as well have let the students study on their own from the beginning; at least that way, they could have used the class time to do test papers.
He shook his head and said,
"Alright, I originally intended to go over your summer exam papers in this class, but judging by this, let's just make up the practical class you missed last time."
A burst of cheers erupted in the classroom, but some students hadn't forgotten.
"The two rolls of Parchment on werewolves, Professor! The two rolls of Parchment on werewolves..."
Sherlock waved his hand and led them towards the practical classroom.
"You don't need to do the assignment Snape gave you; I'll speak to him."
The students' cheers became even more enthusiastic.
The sixth-year practical class didn't progress as quickly as the seventh-year one. In this class, Sherlock mainly focused on teaching them the application of certain spells rather than one-on-one duels.
For instance, the advanced usage of the General Counter-Charm, the advanced usage of the Shield Charm, and so on.
On the same day Sherlock returned to class, Harry also came out of the Hospital Wing.
Madam Pomfrey had insisted on keeping him in the Hospital Wing for so many days, but in reality, his body had been fine since the first day he woke up.
However, what saddened Harry was that when he fell, his flying broomstick had been blown onto the Whomping Willow by the wind and torn to pieces by that temperamental tree.
That made him even sadder than losing the Quidditch match.
That Nimbus 2000 was not only the flying broomstick that had accompanied him for three school years, but it was also a gift from Professor McGonagall after he joined the Gryffindor Quidditch team.
Back in class, Professor Lupin had finally returned as well. This was the only thing that could make Harry feel a little better.
In this class, Lupin also cancelled the assignment Snape had given them and continued with their previous teaching schedule, talking about a Dark Arts creature that lived in the water—the Hinkypunk.
After Snape left the Defence Against the Dark Arts class, all the students in the Castle felt relieved; his painstaking efforts seemed to have gone to waste.
Except for Sherlock, no other student suspected the reason why he had been so stubborn about teaching werewolf knowledge in class.
After the Defence Against the Dark Arts class ended, Lupin kept Harry behind to ask about the Quidditch match.
Lupin hadn't watched that match, so he had only found out what happened afterwards.
He explained the Dementors' abilities to Harry, comforting him by saying that being afraid of Dementors wasn't his problem but rather that the fear Harry had experienced was much more terrifying than what others had gone through.
Harry was clearly still troubled by this because, right before he fainted on the pitch, the sound of his mother being killed by Lord Voldemort had appeared in his mind.
"You used a spell on the train to make that Dementor retreat," Harry said suddenly.
"There are certain defensive methods people can employ," Lupin said, "but there was only one of those things on the train at the time. The more of them there are, the harder they are to resist."
"What kind of defensive methods?" Harry asked immediately. "Can you teach me?"
Lupin looked at him, shook his head, and smiled.
"To be honest, Harry, I'm not really an expert in researching Defence Against the Dark Arts, and dealing with Dementors is certainly not my speciality."
"But only by mastering the way to deal with them will I no longer be afraid of them!" Harry said firmly.
Lupin looked at him, hesitated for a moment, and then gave him a suggestion.
"If you really want to learn, I suggest you go find Sherlock. He is the expert in this area. Before I came to teach at Hogwarts, I specifically read the book he wrote about Dark Arts creatures. His understanding of Dementors is top-tier in the entire Wizarding World."
Harry was stunned.
"Professor Cavendish?"
"Yes, Sherlock. He is indeed brilliant; he is at the forefront of the Wizarding World in the research of Defence Against the Dark Arts. Besides, I have some things to attend to before this Christmas. Getting sick really came at a bad time."
It wasn't that Harry didn't want to learn from Sherlock. Because of their travel experience together during the summer holidays, it could be said that Sherlock was the teacher Harry was closest to in the Castle.
But precisely because they were close, Harry knew better that unless there was something very important, he shouldn't always hang around Sherlock; otherwise, he would always encounter some terrible "blessing" in inexplicable places.
But Harry really wanted to learn the magic that could deal with Dementors this time. Hearing Lupin's recommendation, Harry finally decided to follow his advice and go find Sherlock.
When Harry arrived at the office, Sherlock was marking the fifth-year assignments.
He heard Harry's request and looked up at him in confusion.
"How did you know to come to me to learn this?"
"Professor Lupin told me. He said you are an expert in Defence Against the Dark Arts. I asked him to teach me earlier, but he said he wasn't good at dealing with Dementors and that he had other things to attend to."
Sherlock didn't pay attention to the flattery earlier. Instead, he noticed Harry's last sentence.
"Lupin said he has other things to attend to?" he asked, rubbing his chin.
Harry didn't know why Sherlock would ask this, but he nodded honestly and said,
"Yes, Professor. Lupin said his illness came at a very bad time."
Sherlock pondered for a moment, then stared at Harry and asked,
"Is he very pale, and does he look physically weak?"
Harry followed Sherlock's words and recalled what Lupin had looked like when he saw him.
"The Professor does seem physically weak, and his complexion has always been very pale."
Sherlock muttered to himself,
"It's very similar, but it can't really be... can it?"
"What is it?" Harry asked blankly.(TN: Dense as hell, truly.)
"Nothing." Sherlock changed the subject. "Since you want to learn it, I naturally won't refuse. However, the Patronus Charm is not a simple defensive spell; it is very difficult to learn, and you need to be prepared for long-term study."
Harry's gaze was firm.
"I won't give up halfway, Professor."
"Then follow me and study hard. Starting today, come to my office every Saturday and Sunday evening, and I'll teach you how to use this spell one-on-one."
Sherlock and Harry agreed on the time. After Harry left, Sherlock sat in the office thinking for a long time. In the end, he decided that rather than simply guessing, it would be better to ask directly.
Near lunchtime, Sherlock left his office and found Lupin, who looked significantly more lethargic than before.
"Do you want to go to the Great Hall and eat something together?" Sherlock asked, leaning against the doorframe.
Lupin smiled and declined.
"You'd better go yourself; I still have some things I haven't finished."
"Actually, I also have something I want to ask you."
Upon hearing Sherlock's words, Lupin froze. Then, as if he understood something, the smile on his face became slightly bitter, and he sighed before standing up from his chair.
"Alright, let's talk while we eat."
They walked to the Great Hall. Neither of them spoke on the way.
There weren't many people in the Great Hall; it wasn't quite lunchtime yet, and it would be another half hour before the students arrived in larger numbers.
There wasn't a single person at the Professors' table on the dais.
Not all Professors were accustomed to coming to the Great Hall for lunch. More often than not, they would have the House-elves deliver lunch to their offices.
Sherlock and Lupin sat together, with no one else around them.
"Snape taught a lot about werewolves while he was substituting. The students are complaining incessantly, saying he acts as though he has a Werewolf as an enemy."
As Sherlock spoke, Lupin calmly drank his pumpkin porridge.
"You told me before that you had done something to wrong Snape. So, is the Werewolf he's referring to you?"
The scene suddenly fell silent.
After a long while, Lupin, still holding his bowl of pumpkin porridge, spoke softly.
"I didn't expect you to ask so directly."
Sherlock shrugged.
"I actually don't like talking in circles. Usually, if there's a question and I think it's appropriate, I'll ask it directly. If it's not appropriate, then I'll wait for the right time."
"Indeed, if you're suspicious about something, asking directly to clarify it is often the best approach." Lupin took a deep breath and nodded in acknowledgement.
"Snape's implication wasn't wrong. There is indeed a Werewolf at Hogwarts now, and that person is me."