As soon as Christmas passed, it was time once again for Sherlock to give Harry his tutoring sessions.
When Harry arrived at Sherlock's office that evening, he was in a very bad mood.
Because Hermione had informed Professor McGonagall, the Professor had taken away the Firebolt flying broomstick he had received from an unknown sender to inspect it.
Although Harry understood that Hermione was doing it for his own good, he couldn't help but feel angry with her.
Sherlock clearly noticed Harry's mood. He tapped the desk with his wand and spoke.
"I suggest you pull yourself together and try to be more cheerful, because I've invited a special gentleman to be your sparring partner today."
Harry was immediately intrigued by Sherlock's words.
"Who is it? Professor Lupin?"(TN: Dumb to the core.)
"How could Lupin possibly be your sparring partner for the Patronus Charm?"
Sherlock shrugged. He didn't keep him in suspense any longer, but lightly waved his wand at a cabinet in the corner. The silver threads wrapped around it vanished instantly, and a black-robed creature that looked like a mass of sludge rolled out from inside.
Harry looked at the creature, stunned at first. After carefully observing the figure slumped on the floor, he realised it was actually a living Dementor!
Upon recognising it, Harry's eyes widened, and he instinctively jumped back a step.
"Pr-Professor! The sparring partner you mentioned is this thing?!"
The Dementor, which had been tortured half to death by Sherlock over the past few days, squirmed on the ground for a long time before wobbling as it floated upright.
It wouldn't die, and its self-healing ability was extremely powerful. It would slowly regain its strength even without feeding. Of course, if it consumed enough food, its recovery speed would be even faster.
Hearing Harry's question, Sherlock nodded and said,
"A while ago, I invited this gentleman outside Hogwarts to be a guest in my office. He not only generously agreed but also very politely expressed a desire to repay me. So, I asked him to help me with a small favour and, while he was at it, serve as your sparring partner."
Hearing Sherlock's words, Harry wore an expression that clearly said, Who are you kidding?
Over the past few days, he had learned a great deal about Dementors and knew very well that they were impossible to communicate with under normal circumstances, let alone invite as guests or persuade to offer repayment.
Sherlock must have simply captured it himself.
As they were speaking, the Dementor had slowly recovered some energy. It sensed that, besides that demon, there was also a fresh and delicious source of food in the room.
It didn't dare provoke that wicked demon, but it greedily wanted to absorb the fragrant happiness and hope from Harry.
At the same time, Harry felt his body grow deathly cold. His mother's pleading voice before her death began to ring in his ears once again.
The Dementor floated over from the cabinet, a blurred, transparent, gauze-like connection forming between it and Harry.
Sherlock did not step in to stop the Dementor from draining Harry's positive emotions. Instead, he gave a loud shout that startled Harry, whose eyes had already begun to glaze over.
"Use the Patronus Charm I taught you!"
Harry snapped out of his daze instantly, but he still felt that chilling cold deep within his heart, and his whole body couldn't stop trembling.
Gritting his teeth, he raised his wand at the Dementor, which was still slowly floating towards him, waved his arm, and chanted the spell.
"Expecto Patronum!"
But no strands of light emerged from the tip of his wand. The Dementor was not affected at all; instead, it had already floated right in front of Harry!
At that moment, a silver strand of light suddenly bound it. Then the thread retracted, pulling the Dementor back into the cabinet in the next instant, and finally, the cabinet door slammed shut once again.
Harry's eyes, which had turned hollow, regained their light. He gasped for air as though he had just returned from the brink of death.
Sherlock lowered his wand and handed him a cup of hot chocolate that had been prepared on the desk.
Harry took the cup with trembling hands and said sadly,
"I'm sorry, Professor. As soon as I saw it, I heard my mother's voice in my ears, and I couldn't concentrate enough to use the Patronus Charm."
Sherlock had expected this.
Using the Patronus Charm during normal practice is completely different from using it when facing a Dementor in terms of both feeling and experience.
The aura of despair emanating from a Dementor is enough to intimidate a Wizard.
It makes it impossible for them to recall even a shred of happiness from their memories, causing spells they might otherwise have been able to cast to fail at the critical moment.
However, it is also under the immense pressure of facing a Dementor that a Wizard's potential is more easily stimulated. Once they overcome the influence of the Dementor itself, it is of great help in learning and mastering the Patronus Charm.
Sherlock comforted Harry.
"When you face a Dementor, the fear you have to endure is much greater than what others experience. But those emotions can also become your motivation, Harry. Don't dwell on the despair your mother felt when she was pleading. Think instead about the courage and strength she showed when she wanted to protect you. She shouldn't be an obstacle to your learning the Patronus Charm, but your motivation."
Harry held the cup of hot chocolate, listening to Sherlock's words, and his gaze gradually became more determined.
He sat in the chair and rested for a while before standing up.
"I want to try again, Professor."
Sherlock naturally granted his request. He waved his wand again, the cabinet door opened once more, and the Dementor was released from its restraints, slowly floating out of the cabinet.
But this time, after emerging, it huddled to one side and didn't dare move forward at all.
Even if its thinking was simple, it didn't mean the Dementor was an idiot.
It knew very well that the tempting food was nothing more than bait! It could only look. Before it could even begin feeding, it would be shut back into the cabinet by that demon.
So this time, it had no intention of falling for it again.
Seeing that it wasn't cooperating, Sherlock's brow twitched. A silver thread shot from the tip of his wand, dragging it directly in front of Harry.
But even so, the Dementor still refused to cooperate. It restrained its desires and no longer adopted a feeding posture, merely emanating the bone-chilling cold it couldn't control.
Faced with this attitude of non-violent non-cooperation, Sherlock naturally didn't indulge it. He tightened the strands of light binding it and threatened,
"If you cooperate honestly, I'll let you go once my student has learned the spell. But if you don't cooperate, once my experiment is over, I'll throw you onto the black market and sell you to other Wizards!"
The Dementor seemed to understand his words. It shuddered all over and hesitantly resumed its feeding posture towards Harry.(TN: Hilarious)
Seeing Sherlock bully the Dementor like this, Harry couldn't help but feel a little sorry for it, and his fear of it wasn't quite as intense anymore.
It was that bone-chilling cold again. This time, Harry gripped his wand tightly. When the Dementor began feeding on the positive emotions within him, his mother's voice rang in his head once more.
He didn't tremble anymore. Instead, with his body tense, he steadily waved his wand.
"Expecto Patronum!"
The pronunciation of the spell perfectly matched the tone Sherlock had taught him, without a single error.
The next moment, a huge silver shadow suddenly erupted from the tip of his wand. The shadow circled between him and the Dementor. Although Harry felt his legs were incredibly weak, he remained standing on his own, though he didn't know how much longer he could stay upright.
The moment Harry's Patronus Charm took effect, the Dementor darted backwards with remarkable speed and finally shrank back into the wooden cabinet specially used to contain it.
Seeing that Harry had already taken a huge step towards success, Sherlock was not stingy with his praise and clapped his hands.
"Very good, Harry! I didn't expect you to progress so quickly under pressure!"
This was indeed beyond Sherlock's expectations. He had originally thought it would take Harry quite some time before he could summon even a rudimentary Patronus, but he hadn't expected facing the pressure of a Dementor directly to be so effective, allowing Harry to reach this stage already.
He took another piece of chocolate he had prepared earlier from the drawer and handed it to Harry.
"Eat all of this. You've done very well. What's left is simply long-term practice to become familiar with that feeling."
But Harry didn't seem very excited.
"I still couldn't summon a Patronus like you did, Professor."
Sherlock laughed involuntarily.
"Don't be too hard on yourself. Do you know how long it took me to learn the Patronus Charm?"
Harry looked at him in confusion. Sherlock held up one finger.
"A year. It took me a whole year to fully master this spell. If you could use it after less than a month of learning, wouldn't that make my talent look terrible?"
Harry said gloomily,
"You certainly didn't have anyone teaching you, and no one caught a Dementor for you to use as a sparring partner."
Sherlock shrugged.
"Even taking those factors into account, you're already excellent, Harry. There are no shortcuts to success. To master the power you can control, what you need is long-term, persistent effort."
Harry looked around at the three full bookcases filled with magic books in Sherlock's office, sensing that what Sherlock said was exactly what he himself had been doing.
"I'll work hard, Professor!"
"Work hard again next week. It's very late now, and you're already very tired. Go back and get some rest."
That night, Harry returned to the Gryffindor Common Room.
He hadn't told Sherlock about his discovery regarding Black. He hadn't mentioned it again over the past few days. Hermione and Ron both thought he had forgotten about it, but in fact, he had always kept it firmly in his heart.
After the Christmas holidays ended, the students returned to the Castle, making Hogwarts lively once again.
With the start of the second half of the school year, the fifth and seventh-year students had also entered the final sprint before their examinations.
Sherlock had set up an orderly study plan for them, ensuring that almost no time was wasted each day.
Even George and Fred, who were usually the most mischievous, had now become diligent and hard-working. This wasn't because they had suddenly changed their minds and wanted good grades to find jobs in the Ministry of Magic.
Rather, the academic atmosphere around them had changed.
When all the fifth-year students were studying, and no one appreciated their pranks or cheered for their creativity anymore, Fred and George unknowingly joined everyone else.
In the fifth-year classroom, Sherlock used the Levitation Charm to bring in a stack of exam papers nearly half as tall as a person.
"In the past, there was very little material available for the theory exams. I compiled and wrote these last year, and added a bit more this year. There are seventeen exam papers in total, covering all the question types from previous Defence Against the Dark Arts theory exams. As long as you master these questions, getting a perfect score on the theory exam will be a simple matter."
"I've bound them into a booklet and will hand them out to you in a moment. You are to complete one of these seventeen papers each week for the rest of the semester. I will go through them one by one in class, and we should be able to finish all the papers by April. Then we will begin intensive training for the practical exam."
"The practical exam in the Ordinary Wizarding Level examinations is actually the easiest part in which to score marks. The Ministry of Magic won't choose any particularly troublesome Dark Arts creatures for you; the highest danger level will only be XXX. The weaknesses of these magical creatures and how to deal with them are things we've covered countless times."
The students below were all listening very attentively. The fifth-year Ordinary Wizarding Level examinations could be said to be the most important exams in any Wizard's academic career.
These examinations were equivalent to their basic educational qualifications in the Wizarding World; they would only have one opportunity to perform well.
The seventh-year N.E.W.T.s were more like advanced examinations. The higher the level, the less important they were compared with the Ordinary Wizarding Level examinations.
Sherlock waved his wand, distributing the exam booklets to every student while beginning today's lesson.
"I hope you haven't forgotten too much of what I taught you last semester over the holidays. First, the Shield Charm—does anyone remember the incantation for its advanced application?"
Almost immediately, the students raised their hands in unison. Sherlock randomly pointed to a boy.
"The incantation is Protego Totalum, Professor."
"And can you tell me what changes occur in the effect of the Shield Charm after using the advanced incantation?"
The boy clearly had a thorough understanding of the material and answered without hesitation.
"The Shield Charm expands its area of protection and provides the caster with protection from all directions. However, if the spell is not mastered proficiently, the Wizard must cast it in advance; otherwise, gaps can easily appear in the protection."
"A perfect answer. Five points to Ravenclaw!"