"That must be those two brothers from the Weasley family. Seeing that Harry couldn't go to Hogsmeade this year, they gave this map to him."
Lupin guessed the reason.
As he said this, he got up from his chair, put on his coat, and prepared to go out.
Sherlock, however, stared at the Marauder's Map and said thoughtfully,
"Doesn't this map allow you to see the movements of everyone inside Hogwarts? Perhaps we can use this to find Black."
Lupin shook his head.
"Hogwarts is very large, and there is a lot of information compressed onto this map. Not to mention whether we could find Black on the map the moment he sneaks into Hogwarts, who in the school would have the time to keep staring at it?"(TN: Use magic to track only Black.)
What he said made a lot of sense, but Sherlock always felt there must be another reason why he rejected the proposal. However, he didn't dwell on it, nodded, and followed Lupin out of the Castle.
The moon had already risen and was hanging in mid-air, emitting a pale white glow. Lupin's spirit hadn't changed much, but his complexion looked exceptionally pale under the moonlight.
Sherlock watched his condition and asked curiously,
"Before transforming, do you not have any other feelings?"
Except for his overly pale complexion, Lupin's emotions and spirits appeared quite normal, and he explained,
"The closer it gets to the time of transformation, the more exhausted my body feels. Physical fatigue leads to the inability to use many high-level spells, or an inability to cast spells for long periods."
Sherlock could understand this.
To be precise, Wizards in this world do not have a 'mana bar'. The magic power within a Wizard is more like a representation of magical strength—the stronger the magic power, the stronger the magic cast; it is not a consumable energy.
If one were forced to assign a 'mana bar' characteristic to an attribute, it would be more like physical stamina.
Prolonged spellcasting makes a Wizard exhausted, and their stamina drops quickly. Students basically have no restrictions when practising spells; if they feel tired, they can rest for a while and then continue practising.
Theoretically, as long as a Wizard's physical fitness is sufficient, they can cast spells without limit.
This is also the reason why Sherlock insists on getting up to exercise every morning; his floating wand spellcasting system consumes a lot of stamina.
Casting spells with two hundred and one wands at once—after using it three times, his body would be exhausted. He could barely manage a fourth time, and by the fifth, he would be lying on the ground, completely drained.
And this is with the effect of the spells already reduced.
Overall, under normal spellcasting circumstances, with Sherlock's physique, he could cast between five hundred and six hundred spells in a row before his body would be drained.
Meanwhile, Hogwarts students, who are still in their developmental years and do not usually pay attention to exercise, would normally collapse from exhaustion after casting about two hundred spells and would begin to feel physically tired after a hundred.
But given the teaching intensity at Hogwarts, it is very, very rare for students to practise up to one hundred spells a day, so learning magic is effectively limitless for them.
Moreover, in a normal Wizard duel, the outcome is usually decided within ten spells. It is impossible for two people to continuously exchange two or three hundred spells without a winner being decided.
Therefore, there is no such thing as a 'mana bar' in this world; as long as you can cast, you can fling spells as you please.
Except for an anomaly like Sherlock, who can release two hundred spells at once.
Sherlock had been researching the optimal combination of wands for spellcasting. Last time, when facing the straw man, two hundred Patronus Charms were clearly overkill. Even if he had used only one hundred, with proper coordination, he could have achieved the same effect.
Two hundred beams of magical light flying all over the sky might look extremely intimidating, but what they consumed was Sherlock's stamina.
Lupin brought Sherlock to the Whomping Willow, located next to the Forbidden Forest. The willow tree was violent and aggressive; no normal person could get anywhere near it.
When they were still more than ten metres away from the willow tree, Lupin waved his wand at a small pebble on the ground.
The pebble instantly turned into a squeaking mouse, which ran quickly and darted onto the trunk of the Whomping Willow.
It seemed to touch a certain knot on the willow's trunk, and the irritable magical willow immediately became still.
Lupin brought Sherlock to an entrance to a tunnel near the base of the trunk, and the two of them crawled inside together.
"This Whomping Willow was planted by Dumbledore specifically the year I enrolled, and this secret passage was also prepared by him for me. When I was at school, every time the day of transformation arrived, he would have the school nurse, Madam Pomfrey, bring me here, and then have me travel through this secret passage to the Shrieking Shack in Hogsmeade to transform and spend the night as a Werewolf, so as not to harm anyone else."
Lupin recounted his past experiences to Sherlock.
Sherlock could clearly hear that his words carried some emotion, as well as a sense of loneliness that he seemed to want to hide but couldn't.
He didn't ask more about it; everyone has their own little secrets, and he was no exception.
They travelled through the tunnel for about half an hour and finally arrived at a dirty, dilapidated shack.
This was the famous haunted house in Hogsmeade, or indeed the entire British Wizarding World—the Shrieking Shack.
Sherlock looked at the house and, associating it with the time when the Shrieking Shack's reputation as a haunted house began to spread, he could probably guess what had happened.
"This place is called a haunted house because people used to hear strange screams in the middle of the night. That was the noise that spread after you transformed here during your school days, wasn't it?"
Lupin nodded.
"Yes. In fact, the rumours spread because Professor Dumbledore deliberately encouraged them, so that no one would venture in here while I was transforming and get hurt by me."
"But in fact, there was one time it almost happened?" Sherlock blinked.
Lupin looked at him in astonishment.
"You... you know about that?"
"Snape told me." Sherlock sighed. "I asked him why he hated you so much, and he told me it was because, back when you were transforming, your friends tricked him into coming in, and he was almost bitten to death by you after you became a Werewolf."
Lupin fell silent. His expression was miserable, as though he were recalling some painful memories.
"We were indeed too immature and went too far back then, especially Sirius."
Sherlock was stunned for a moment upon suddenly hearing this familiar name, but then he immediately reacted.
"Who did you say?"
Lupin seemed to realise he had let something slip, but he didn't appear to mind Sherlock knowing. However, just as he was about to answer, his face suddenly became ferocious.
"Wait. Let me tell you more later, Sherlock..."
Sherlock also realised that this was the precursor to Lupin's transformation. He stepped back a few paces to ensure he had enough casting distance in case of an accident, while observing Lupin's Werewolf transformation.
A painful roar rang out. Lupin's head elongated, and his body also grew larger.
His shoulders hunched, hair grew across his face and hands, and his fingers curled into sharp claws.
An upright Werewolf stood before Sherlock. Compared to an ordinary wolf, a Werewolf in its transformed state had a slightly shorter snout and slightly smaller pupils, making it look more human. However, the combination of a human physique and a wolf's appearance made the Werewolf look exceptionally grotesque.
After transforming into a Werewolf, Lupin stared at Sherlock with those beast-like eyes, but there was no savagery or cruelty in them, only calmness.
This was clearly the effect of the Wolfsbane Potion he had taken beforehand.
Studying the Werewolf transformation was the main purpose of Sherlock and Lupin coming together, but now Sherlock had no mind for that. Instead, he stared into Lupin's eyes and asked,
"You said your friend from your school days was Sirius Black?"
Lupin, covered in grey-black fur, gestured for Sherlock to sit down and talk. Neither of them cared about the dusty floor of the Shrieking Shack and sat directly on the ground.
"I received news that you joined the Order of the Phoenix last year, Sherlock." Lupin's voice in his Werewolf form was rough and deep, but it still retained its characteristic gentleness. "So, even if I don't tell you some things now, you will learn them in the future."
Sherlock did not speak; he listened quietly as Lupin recounted his story.
"Dumbledore is a kind Headmaster. After learning that I was a Werewolf, he still specially approved my admission to Hogwarts. Here, I not only learned magic but also made several very good friends."
"I was always afraid that if they discovered I was a Werewolf, they would distance themselves from me. But later, they discovered my secret through various clues."
"Being a Werewolf did not become an obstacle to our friendship. They were still willing to stay by my side, and later they even learned high-level Transfiguration for my sake, so I wouldn't have to transform here alone."
Hearing this, Sherlock naturally guessed who those friends from Lupin's school days were.
"So Sirius Black and James Potter were both your friends?"
"How did you know about James?" Lupin asked in surprise.
"Before the start of the school year, Mr Weasley specifically found me and told me the story of how Black betrayed Harry's father. I knew they had been very close friends before, so since Black was among your friends, Harry's father would naturally have been there too."
Lupin nodded, his gaze filled with pain.
"Sirius, James, and Pettigrew—they were all my friends."
"Peter Pettigrew?"
Yet another familiar name. It wasn't just Mr Weasley who had mentioned it to him at the Leaky Cauldron; Sherlock always felt he had seen or heard the name somewhere before, but no matter how hard he tried, he couldn't remember where.
"Yes, Peter Pettigrew. The four of us were inseparable back then, but you already know what happened later. Black betrayed James, leading to his and Lily's deaths. Afterwards, Peter tried to stop Black and avenge them, but he too was blasted apart by Black's spell, leaving only a finger behind!"