Hogsmeade was now crawling with patrolling Aurors.
On his way to Hogwarts, Sherlock had already been stopped and questioned three times, even running into Tonks once.
She had only just finished her internship, and normally her main duties would have been office chores, but there was such a shortage of personnel now that she had also been sent out on assignment.
Such a large number of Aurors gathering in Hogsmeade was, of course, not just to catch the murderer from Germany; their primary objective was to arrest Black.
After all, although there had been seven known attacks, five involved Muggles and only two Wizards had died so far, which wasn't enough to overshadow the news of Black's escape.
But anyone in the know understood that the attack cases were actually far more troublesome than the Black situation.
Because for these cases occurring within Britain, the British Aurors had yet to grasp any key clues; the most vital information was held by the three German Aurors.
Sherlock didn't know if the German Ministry of Magic had shared the murderer's files with the British side.
To catch Black, they could only think of waiting around Hogwarts, and it seemed they were also planning to tackle the attacker's case here in Hogsmeade.
With both matters converging on Hogwarts, a heavy sense of urgency had already set in even before the new term had begun.
Sherlock reached the end of the Hogsmeade street. Just as he was about to head towards the Hogwarts gates, he suddenly noticed a large black dog curled up next to a rubbish bin in a small alley.
The dog looked like a stray, but it was quite large and its fur was sleek and shiny; it was clear at a glance that it had once been well cared for before being abandoned.
The dog only caught his attention briefly; Sherlock was not an animal rights activist and had no intention of adopting it.
He walked through the gates of Hogwarts. The school was still very quiet, but the figures of Dementors could already be seen on both sides of the gate.
As Sherlock entered, they floated over, intending to perform some kind of inspection on him.
He didn't resist; the two Dementors stared at his face as if to determine whether he was the escaped Black.
At that moment, a cold, desperate aura suddenly emanated from one of the Dementors. Sherlock could clearly feel his body temperature dropping, while the positive emotions within him were being sucked out.
The moment he sensed the problem, he didn't hesitate and drew his wand!
"Expecto Patronum."
A brilliant silver light erupted!
Countless silver threads of light gushed from the tip of his wand!
The two Dementors immediately let out silent shrieks. Their grey robes were being constantly worn away under the relentless erosion of the silver light.
It wasn't until their bodies began to turn ethereal, on the verge of being completely wiped out, that they managed to break free from the entanglement of those silver threads.
They floated away in a panic, not even daring to look back at Sherlock.
"Bullying the weak and fearing the strong," Sherlock sneered.
From the behaviour of these Dementors, he was certain that if they remained stationed near Hogwarts, there would definitely be trouble this term.
They were used to being audacious, and since they didn't have a constant supply of food here to keep them full like in Azkaban, they were very likely to take extreme actions.
However, this wasn't something Sherlock needed to worry about for now; Dumbledore would surely understand this better than he did.
Sherlock entered the Castle. Just as he reached the entrance hall on the first floor, he ran into Professor McGonagall, who was frowning as if lost in thought.
"Good morning, Professor McGonagall," Sherlock greeted her.
Professor McGonagall saw him, and her brow immediately smoothed out. Her face wore a gentle smile that she didn't often show.
"Good morning, Sherlock. You've come at just the right time. After you've put your things away, you need to go to the Headmaster's Office. The password is 'Lemonade'. Albus has something to discuss with you."
Sherlock nodded, indicating he understood.
He and Professor McGonagall parted in the entrance hall, and he went to his office on the third floor to put his things away.
Even though he hadn't been back for two months, there wasn't much cleaning to do; the House-elves in the Castle took care of the regular cleaning.
Then he left his office, walked to the end of the third-floor corridor, and stood before the gargoyle at the entrance to the Headmaster's Office.
"Password," the gargoyle asked in a muffled voice.
"Lemonade," Sherlock replied.
In fact, sneaking into the Headmaster's Office was quite simple; you just had to list the sweets Dumbledore liked, and one of them would inevitably be the correct password.
The gargoyle jumped aside, clearing a path for him.
Sherlock walked in, then followed the spiral staircase up to the eighth floor and pushed open the door to the Headmaster's Office.
Dumbledore was reclining in his chair with his eyes closed, as if deep in thought.
The former headmasters in the portraits on the walls were still snoring softly, as though they could never sleep enough. Fawkes was on a nearby golden perch, preening his bright red feathers with his beak.
Hearing the movement, Dumbledore opened his eyes. He looked at Sherlock as he walked in and smiled.
"Did you have a good holiday?"
Sherlock sat down across from Dumbledore, and a cup of steaming black tea automatically appeared in front of him.
"It was quite good, actually. France was nice, and the food there is much better than here."
"I received a letter from Nicolas. He told me everything that happened. You and Harry actually received the French Wizarding Medal of Friendship awarded by the French Ministry of Magic."
Dumbledore looked somewhat surprised; evidently, he hadn't expected Sherlock and Harry to have such an experience.
Sherlock waved it off.
"We didn't expect that to happen either. That wand thief was certainly bold, even daring to impersonate Nicolas Flamel. If I hadn't discovered the issue because he also wanted to be a human trafficker, he might have actually succeeded."
They chatted about their holiday experiences for a while, and then Dumbledore spoke about the reason he had called him over.
"When you arrived at Hogsmeade, you must have seen the situation there."
Sherlock nodded.
"Troubles are piling up, and the problems are all happening here at Hogwarts."
Dumbledore's blue eyes grew deep, and his half-moon spectacles reflected the white light.
"The Black matter is relatively easy to solve, but the attack case is a big problem."
He clearly saw things more clearly than most.
"You met Ms Hilke last term. She came to Hogwarts a while ago to find me, saying she wanted to stay in the Castle temporarily."
Sherlock frowned.
"She thinks the murderer will come to Hogwarts."
"It's not that she thinks so," Dumbledore shook his head and said meaningfully, "but that she saw that thing will come to Hogwarts."
Sherlock was slightly stunned.
Dumbledore's words seemed a bit mysterious, but Sherlock recalled seeing Ms Hilke's true appearance in front of those two graves in the Forbidden Forest at the end of last term.
What he remembered most vividly were those eyes covered by a ribbon.
"She is... a Master Seer?"
"In some aspects, she can see a bit more than we can." Dumbledore didn't say it explicitly, but he had essentially confirmed it.
Sherlock asked curiously.
"I was curious last time. Isn't she a German witch? Why did you agree to let her father be buried in the Forbidden Forest at Hogwarts?"
Hearing Sherlock's question, a look of reminiscence appeared on Dumbledore's face, and he said softly.
"Ms Hilke's father was once an Auror for the British Ministry of Magic. He died in the line of duty over ten years ago, and her mother took her to Germany."
After hearing Dumbledore mention this, Sherlock didn't ask any more questions.
An Auror who died in the line of duty over ten years ago and could make Dumbledore show such an expression could only have died in the struggle against Lord Voldemort.
In that case, it wasn't surprising that he would agree to have him buried in the Forbidden Forest.
"I agreed to her request to stay at Hogwarts, but I also required that someone must accompany her while she investigates this case."
"This was also Fudge's request to me. He doesn't trust these three German Wizards. They have repeatedly requested that the German side share information about the murderer with them, but the German Ministry of Magic has always found excuses to delay."
"The Ministry's Aurors are currently in very short supply, not only to investigate the Black matter but also to maintain normal order in the Wizarding World. So he hopes I can send a Professor to monitor their movements at all times, to prevent them from doing anything harmful to the interests of the British Wizarding World."
Sherlock understood Dumbledore's meaning; he had chosen him to be this monitor.
"Then what about my teaching duties at the school?"
Dumbledore had obviously already made arrangements.
"Your teaching assistant for this year, Remus Lupin, is likely already on the Hogwarts Express. With him, your teaching load won't be as heavy, and you'll have more time to focus on other matters."
At this point, Dumbledore suddenly said with a smile,
"I also want to congratulate you, Sherlock. Under your instruction last year, the students all achieved excellent results in Defence Against the Dark Arts in last term's O.W.L.s and N.E.W.T.s. Everyone scored above an A, and over 80 per cent of the students even received Os and Es.
"So I suggest that for this year's Defence Against the Dark Arts classes, you can focus on the upper years, where the students have more exam pressure, and leave the lower-year classes to Lupin for the time being."