"That was a bit too direct, wasn't it? I expected you to deny it for a moment." Sherlock looked at him in surprise.
Lupin met Sherlock's gaze. Although he was dressed in shabby clothes, his frame was thin, and his face was as pale as someone who had been ill for a long time, his eyes were exceptionally bright.
"I'm not a person who likes to beat around the bush either. I thought before that Snape's hint wouldn't make the students realise anything, but it would certainly arouse your suspicion. But to be honest, I didn't expect you to come directly to me and just ask like that."
Sherlock cut the steak on his plate.
"Some things are better asked directly than guessed at blindly. I honestly didn't think Dumbledore would actually hire a Werewolf, but thinking about it carefully, it's quite in line with his character."
Having made things clear, Lupin felt a sense of relief and finished the last spoonful of porridge in his bowl.
"What do you plan to do next? Are you going to tell the whole school, students and teachers alike, about my identity?"
Sherlock chewed his steak and blinked.
"Why would I do that? Even Snape, who hates you so much, only uses such subtle methods to imply your identity, so why would I do something like that?
"I only came to ask you because I was curious. Since Dumbledore knew your identity and hired you, it means he trusts you enough. Besides, we've been working together for three months, and I feel like you're a decent person."
A dumbfounded smile appeared on Lupin's face.
"Actually, I've always felt I didn't deserve Dumbledore's trust. He knew I was destitute and couldn't even afford to eat, which is why he hired me at Hogwarts, but I am, after all, a Werewolf."
Sherlock waved his hand.
"Don't be so lacking in confidence, old friend. I remember not long ago a Wizard developed the Wolfsbane Potion, a Potion that allows a Werewolf to remain lucid during transformation. Isn't that what Snape is specifically brewing for you at school?"
"You guessed that too?" Lupin looked at him in surprise.
"Don't think of me as so omniscient. My grades in Divination when I was in school were so poor that I dropped it after my sixth year. It was Harry who told me; he saw you drinking the Potion Snape prepared and was worried it was poisoned."
"Harry has some prejudices against Snape."
"To be honest, what I find even more interesting is that Dumbledore still lets Snape brew the Wolfsbane Potion for you," Sherlock said, raising an eyebrow. "The fact that Snape wants to expose your identity is enough to show he holds a deep grudge against you. Dumbledore making him brew medicine for his enemy—he really is quite wicked."
Lupin looked bitter.
"Because the only person in all of Hogwarts who can brew the Wolfsbane Potion is Snape."
"The fact that he didn't put any slow-acting poison in it proves that he still has some principles."
"Yes, and for that, I am grateful to him."
Sherlock swallowed the last bite of steak, clapped his hands, and stood up from the chair.
"Alright, I know what I wanted to know, and the matter is cleared up, so now we can say we understand each other."
After confirming Lupin's identity, Sherlock didn't plan to do anything.
He had been somewhat puzzled about how someone as good-natured as Lupin, who was also so popular with students in class, could only serve as a Professor for one year in the original story.
Now it was clear; being a Werewolf meant he could not stay at Hogwarts for very long.
Even with the existence of the Wolfsbane Potion, given the danger posed by a Werewolf, once Lupin's identity was exposed, it would be impossible for him to continue staying at Hogwarts.
Furthermore, with Snape secretly causing trouble in the Castle, whether Lupin could last the full year was still an open question.
However, having someone help shoulder the teaching duties made things easier for Sherlock, and he genuinely hoped Lupin could stay at Hogwarts for longer.
A week passed quickly.
On Saturday evening, Harry arrived at Sherlock's office after dinner, following the time they had agreed upon.
Sherlock was reading a letter, and he didn't hide it when Harry entered.
"Who wrote you that letter, Professor?" Harry asked, scratching his head.
Sherlock didn't hide it from him.
"Fleur."
"Miss Delacour? What did she say?"
"Nothing much, just asking if I'm still teaching at Hogwarts, and talking about what she's been doing at school—it seems she wrote it out of boredom."
Sherlock shook his head, put the letter aside on the table, and began earnestly instructing Harry on learning the Patronus Charm.
"First, tell me how much you know about this spell."
Hearing Sherlock's question, Harry thought for a moment before replying.
"I saw Professor Lupin use it once on the train. It seemed to emit some bright silvery filaments of light from his wand. Dementors are very afraid of those filaments; they don't dare go near them.
"Also, that time at the Quidditch Pitch, when I fell from the sky. Ron and Hermione told me that a silvery-white bird suddenly flew down from the sky. It drove away all the Dementors together, which was even more powerful than just the silver light. That bird must also have been the Patronus Charm, right?"
Sherlock drew his wand and gave it a gentle wave.
"Expecto Patronum."
Bright silver particles sprayed from the tip of his wand and soon formed a bright silver bird in front of Sherlock, which then flapped its wings and landed on Harry's shoulder.
"It's this bird, my Patronus."
Harry looked in amazement at the bird perched on his shoulder and held out his hands. Sherlock's Patronus naturally hopped onto his palm.
He felt a slight chill in his hand, but otherwise there was no sensation of holding anything with weight.
"So this is your Patronus, Professor! The Gryffindor students have all been guessing who summoned it."
Harry observed the silver bird for a long time before finally recognising its species with surprise.
"It's a raven."
After his surprise, he found himself wondering why he had been surprised in the first place.
What else could Professor Cavendish's Patronus be besides a raven?
The raven hopped a few times across Harry's hand before flying back to Sherlock's shoulder, where it silently stared at him.
Sherlock guided Harry, teaching him the wand movement for the Patronus Charm and correcting his pronunciation before having him make his first attempt.
"Expecto Patronum."
Harry waved his wand as Sherlock had instructed.
However, nothing happened. Not even a single silver filament appeared at the tip of his wand.
"The last flick of the wand should be upwards. It doesn't need to be too obvious; just making the motion is enough." Sherlock corrected his technique and reminded him, "Before casting the spell, you need to find the right feeling. This is a spell that demands strong positive emotions; the happier you are, the more successfully you'll be able to cast it. So think of joyful, happy memories before you cast the spell."
Although Harry studied very earnestly and indeed had great talent in Defence Against the Dark Arts, such an advanced spell could not be mastered so easily.
By the time curfew began, Harry still hadn't managed to produce a single filament of light from his wand.
He was a little disappointed, but Sherlock had expected this.
If Harry could really master it in such a short time, Sherlock would have to wonder whether his own talent was ridiculously poor, considering it had taken him nearly a whole year before he could finally summon his Patronus.
After that, Hogwarts enjoyed a period of peace until Christmas.
Black did not break into the Castle a second time. After the Dementors acted recklessly during the Quidditch match, Dumbledore must have warned them, because not a single Dementor dared enter the Hogwarts grounds again.
Hilke had been back in Germany for over a month without sending any reply. If Sherlock didn't know she wasn't the type of person to shirk responsibility, anyone else would have thought she had completely disappeared.
However, during this time, the locket he wore around his neck hadn't shown any abnormalities. Apart from the fact that it couldn't be removed, which made bathing and sleeping somewhat inconvenient, it was no different from an ordinary ornament.
The end of the first term at Hogwarts arrived, and the final week before the Christmas holidays brought another Hogsmeade weekend.
Two weeks earlier, heavy snow had fallen around Hogwarts for several consecutive days, covering the entire Castle in a thick blanket of white. Only recently had the weather begun to clear.
All the students above third year, except Harry, were delighted.
Hermione planned to buy some Pepper Imps from Honeydukes for her parents as a Christmas present; both her mum and dad loved the sweets.
Harry was rather annoyed about being the only one left behind at the school again, but the previous weekend, under Sherlock's guidance, he had finally managed to cast the Patronus Charm well enough to produce several silver filaments of light from his wand for the first time.
That success eased some of the disappointment of missing out on Hogsmeade.
He decided to borrow Classified Flying Broomsticks from Wood and spend the day learning about different broom models in preparation for buying a new one.
Ever since Harry's Nimbus 2000 had been torn apart by the Whomping Willow, he had tried using the school's training broomsticks instead.
But the old Shooting Star models were slow and unstable, and since Harry wasn't short of money in the Wizarding World, he naturally planned to buy a new broomstick.
On that Saturday morning, while everyone else headed to Hogsmeade, Harry said goodbye to Ron and Hermione at the school gates before climbing the marble staircase alone and returning to Gryffindor Tower.
Snowflakes drifted past the windows, and the Castle was unusually quiet.
Just as he reached the middle of the fourth-floor corridor and turned the corner, he spotted Fred and George peering at him from behind the statue of a one-eyed, humpbacked witch.
"Hey! Harry, come over here!"