Harry explained Sirius's background to them, and all the students in the Gryffindor Common Room became interested in him.
Hermione looked up from her busy coursework, and after observing Sirius's fur and appearance, she guessed his breed.
"This is a Husky, a rather fierce breed of large dog, though it seems a bit bigger than a normal Husky."(TN: No way.)
Although Sirius was petted quite a bit by the Gryffindor students, he thoroughly enjoyed the attention.
It even made him somewhat forget that just two days ago, he had been living a life on the run, hunted while pursuing his enemy.
Harry took him for a walk around the Common Room before finally taking him back to Sherlock's office.
As the sky gradually darkened and the Hogwarts curfew began, Sirius transformed back into his human form in Sherlock's office.
Sherlock was busy writing practice exam papers for the seventh- and fifth-year students, and he asked without looking up,
"So, what are your thoughts now?"
Sirius's expression turned solemn; Sherlock's question brought him back to his vengeful mindset once more.
"Harry has many friends, just like James and I once did, so even without me, he can live a good life. But Peter—must die!"
Sherlock put down his quill and locked eyes with Sirius.
"Since you have made your choice, I won't say anything more. The search for Peter can begin tonight."
Under the cover of night, Sherlock, Lupin, and Sirius left the Castle together, accompanied by Hermione's pet, the large ginger cat named Crookshanks.
On the outskirts of the Forbidden Forest, Sirius stroked Crookshanks's head.
"This is the smartest cat I've ever seen. It must have Kneazle blood in it, and since it remembers Peter's scent, it can be a huge help to us."
Crookshanks had a very large face, and at first glance, his features looked as though they had been flattened by something. He wasn't particularly pretty, but he was cute in an ugly sort of way.
Lupin and Sherlock were clearly people he considered trustworthy, as he showed no resistance towards them.
After getting ready at the edge of the Forbidden Forest, the two men, one dog, and one cat entered the forest once more.
Trying to find a mouse in such a vast forest was basically like looking for a needle in a haystack. They relied mainly on Crookshanks and Sirius, in his dog form, to track Peter's scent.
After nearly a night of searching, they were not left empty-handed.
Crookshanks keenly detected Peter's scent beneath a tree, and Sherlock and the others found a few grey mouse hairs there.
This was enough to prove that Peter was currently hiding in the Forbidden Forest and that Sherlock and the others were searching in the right direction.
However, Sherlock and Lupin both had classes during the day, so they couldn't accompany Sirius to search every night; the main force searching for Peter remained the dog and the cat.
To stay informed in time, Sherlock specifically summoned his Patronus to follow Sirius.
If there were any discoveries, Sirius could have the Patronus vanish, and Sherlock would receive the message.
The final exams were drawing closer.
The final Quidditch match of the year, between Gryffindor and Slytherin, which would decide the championship, also began.
Sirius and Lupin both watched the match, and they witnessed Harry leading the team to win the Quidditch House Cup, which Gryffindor hadn't won in eight years.
Sherlock didn't have time to watch the match because, at that moment, Hilke, who was far away in Germany, had sent him a letter.
It mentioned that the German Ministry of Magic's Department of Mysteries had made some progress in deciphering the memories of the straw man, Fedetick. She asked him to wait a few more days, and once the results were out, she would return to Hogwarts.
Sherlock had been wearing the locket around his neck for half a year. During this time, the locket, which had originally been so dilapidated that no one would have bothered to pick it up if it had been lying on the ground, had become increasingly new. Now, it was impossible to tell that it was an ancient item; one could easily believe it was brand new and had just been bought from a magic shop.
Furthermore, when Sherlock held the locket to his ear, he could faintly hear a strange sound coming from inside.
The sound was very faint but rhythmic, a "tick, tick, tick," like the hands of a clock moving.
Every night while wearing the locket, he would try to take it off his neck, but he had never succeeded.
Now, he could only wait for news from Hilke to see whether any useful discoveries would come from the straw man.
After Gryffindor won this year's Quidditch House Cup, Hogwarts's exam week began.
Because the seventh- and fifth-year students had to take the Wizarding Level Examinations organised by the Ministry of Magic, Sherlock's tasks for the end of the term this year were much easier; he only needed to be responsible for setting exam questions for the sixth-year students.
The students he taught were all very nervous; after all, this could be said to be the most important exam they would take in their lives.
Sherlock, however, had great confidence in them because, in the two mock tests leading up to the end of the term, the fifth-year students' results were unexpectedly excellent, and overall, they looked much better than the previous year's batch.
Even George and Fred, those two troublemakers who usually didn't put much thought into their studies, had excellent results in the mock exams, completely shattering the judgement Sherlock had made about them at the beginning of the semester.
Just after the only exam Sherlock was responsible for—the sixth-year students' exam—ended, Sirius, who had been searching for traces of Peter in the Forbidden Forest, finally made an important discovery.
Lupin was still invigilating the exam, so only Sherlock met with Sirius to learn about the situation from him.
"Peter generally only hides in the Forbidden Forest for a week. After a week, he sneaks out and steals food from Hagrid's hut. He has loved sweets ever since we were at school, so even while hiding in the Forbidden Forest, he can't stand not being able to eat them."
Light flashed in Sirius's eyes as he continued.
"Yesterday, Crookshanks discovered Peter escaping from Hagrid's hut. His time for stealing food is basically fixed, which means that next week, on this day, we can try to catch him!"
Sherlock thought quietly for a moment before saying,
"After this exam week ends, the students will wait another week in the Castle for their results. Once the results are out, this year's holiday begins. By then, it's hard to say what plan Peter has or whether he will continue to stay in the Forbidden Forest. So, the time you mentioned next week is very likely our last chance."
Sirius clearly understood this point as well, and his expression turned gloomy.
"From today on, I will stay near Hagrid's hut and keep watch until Peter appears!"
Sherlock nodded. After having his Patronus continue to follow Sirius, he returned to the Castle.
Two days later, on the evening when Harry and the other third-year students took their Divination class exam, Sherlock and Lupin stayed together in Sherlock's office.
They opened the Marauder's Map and, while chatting, kept observing the area around Hagrid's hut.
"Is it almost time for your transformation again?" Sherlock asked, looking at Lupin's face.
Lupin's face was pale. Around the time of the full moon, his physical condition would become very poor, and his ability to cast spells would also be greatly weakened.
Hearing Sherlock's words, Lupin nodded gently.
"It should be tonight. Snape hasn't brought me the potion yet."
"He still holds a lot of resentment towards you. Is it just because you bullied him when you were at school?"
Lupin's face revealed a bitter smile, as though he had thought of something.
"There is also the matter of Harry's mother."
"Hmm?"
A spark of curiosity suddenly lit up in Sherlock's eyes.
"It has to do with Harry's mother?"
"Yes. Snape and Lily knew each other from childhood, but in the end, Lily chose to be with James, who was the person Snape got along with the least during their school days. That made him extremely resentful. He hated James and us, and perhaps he even hated Lily too."
"Is this also the reason for his attitude towards Harry?"
"Snape has indeed transferred his hatred for James onto Harry," Lupin said quietly. "But in the end, he should still have lingering feelings for Lily, and those feelings may have extended to Harry as well. So, he both hates Harry and doesn't want him to come to any harm."
Sherlock clicked his tongue.
"That really is a complicated emotion."
Just then, Lupin suddenly frowned, and his ears twitched keenly.
"Did you hear a strange sound?"
Sherlock, however, looked puzzled.
"No, I didn't hear anything."
Lupin stood up, as though searching for the source of the sound.
"It sounds like a clock... a ticking sound..."
Before he finished speaking, Sherlock's expression suddenly froze.
"Sirius has cancelled my Patronus Charm!"
Lupin, who had been carefully listening for the source of the sound, also froze.
They both looked at the Marauder's Map on the desk, towards the direction of Hagrid's hut.
Among the names of Hagrid, Harry, Ron, and Hermione, there was one strikingly conspicuous name—Peter Pettigrew!
Afterwards, Sherlock and Lupin had no time to dwell on the source of that strange sound. They quickly left the office together and headed towards Hagrid's hut.
Meanwhile, inside Hagrid's hut.
Today was the date of Buckbeak's execution. After finishing their Divination class exam, Harry and the others immediately put on the Invisibility Cloak and came to comfort Hagrid.
But everyone's mood was very low because they all knew that Buckbeak was not a bad Magical Creature, and the charges the Ministry of Magic had forced upon him were nothing but slander.
Hermione was silently shedding tears. When she was about to pour milk into the jug, a rat suddenly fell out of it!
Ron looked at the rat, and with a bewildered expression, called out,
"Scabbers! What are you doing here?"
He grabbed the rat, which was squealing and struggling constantly. At that moment, Hagrid ushered them out of the hut with a heavy heart.
"Go, hurry up and go! I don't want you to see the execution, and besides, if anyone finds out you left the Castle without permission, you'll definitely be punished."
Harry and the others were pushed out of the hut by Hagrid. They put on the Invisibility Cloak and walked back towards the Castle through the night.
Scabbers, who had been placed in Ron's pocket, kept struggling desperately. He seemed to have been frightened by something and was trying with all his might to escape.
Finally, when Ron wasn't paying attention, Scabbers succeeded.
He slipped out from between Ron's fingers and was just about to dash into the Forbidden Forest when a large ginger cat suddenly shot out from the side like lightning and seized Scabbers in its mouth.
Harry and the others all saw this. Ron panicked and ran out from beneath the Invisibility Cloak, chasing after Crookshanks.
"You filthy, stinking cat!"
"Ron!" Hermione called anxiously.
She and Harry exchanged a glance before they both followed, running after him.
The direction Crookshanks was heading was obvious: straight into the Forbidden Forest.
Harry and Hermione followed behind Ron and soon heard him catching up with Crookshanks.
"Stinking cat! Let him go!"
Ron snatched Scabbers back from Crookshanks's mouth. Just as he was rejoining Harry and the others and preparing to hide beneath the Invisibility Cloak again to return to the Castle, a huge dog blocked their path, staring at them with a grim gaze.
Even while searching the Forbidden Forest, Sirius had always been disguised by Sherlock's spell, so Harry immediately recognised him.
"It's the dog Professor Cavendish keeps!"
"Move aside, good dog! Hurry and move aside!" Hermione pleaded with Sirius.
But Sirius had no intention of moving. There was none of the friendliness in his eyes that Harry had seen when he first brought him to the Gryffindor Common Room. Instead, they burned with an intensely fierce light.
Harry had already drawn his wand, but before he could make any move, two distinct sets of footsteps approached.
Borrowing the faint light in the darkness, Harry and the others immediately lit up with joy when they saw who it was.
"Professor Cavendish! Professor Lupin!"
The two people approaching were none other than Sherlock and Lupin.
However, the scene that followed left Harry and the others completely stunned.
Lupin and Sherlock paid no attention to their calls. Instead, with grave expressions, they drew their wands and aimed them ahead.
At that moment, Sirius also ended his Animagus transformation, holding the wand Sherlock had temporarily lent him, and aimed it at Harry—or, more precisely, at the rat in Ron's hand.
Harry stared blankly at Sirius's face, then at Lupin and Sherlock. The disbelief in his eyes seemed about to overflow.
"Professor... how could you..."