Messing with Sirius, with McGonagall joining in

On a September night with a full moon, past midnight, thin clouds drifted by, revealing the moon and illuminating the western spire.

Most of the Castle windows were dark, but one window under the tower remained lit, casting a shadow on the stone wall.

Regulus stood on the ramparts of the Astronomy Tower, with the tower wall dozens of meters high beneath his feet. The night wind blew against him from above, causing the hem of his school robe to flip over his legs and then fall back down.

The Black Lake was bathed in moonlight; with the slightest movement of the water, silvery-white spots would scatter, only to soon coalesce back into one spot.

The outlines of the tree canopies are visible at the edge of the Forbidden Forest, blending into a deep black expanse. The grassy slopes by the lake extend into the courtyard, the stone steps are empty, and the wind blows through the towers, carrying the coolness of the lake water.

He lifted his face and let the wind blow on him for a while.

He liked Hogwarts at this moment; he didn't have to do anything for the time being, and it was nice to just stand there and watch.

Three figures suddenly appeared on the grass, circled around from the side of the Castle, and jogged along the slope towards the Whomping Willow.

James Potter was at the front; after running a few steps, he turned back and waved, waving his arm vigorously.

Sirius, hands in his pockets, with his long legs and big strides, followed with ease, his posture still as dashing as ever.

Peter Pettigrew lagged behind, his robe caught on his leg, and he stumbled, quickly picking himself up and continuing to chase. After running a few steps, he turned back to look at the Castle, fearing that Filch might be watching them from behind one of the windows.

Regulus lowered his head, his gaze falling on Sirius. "So energetic in the middle of the night."

He just had some fun underground before school started, which gave him about ten days of freedom, so it's time to get back to it.

They also went out at night, following James as he explored the Castle, which they called adventure.

Sirius's mood and when he feels it's worth going out and having some fun depend entirely on his mood that day.

At least if you have Big Dog, you can set a time for it to be walked. But when it comes to him, you have to guess the time on the spot.

There's no need to go looking for him every night, and then spend half the night with him after you find him. It's easier on a full moon night. Just look in the direction of the Whomping Willow" (a local landmark), and you'll be blocked every time.

Regulus's lips curled up slightly.

Since we've run into each other tonight, let's keep going! Sirius was laughing quite happily; there'll be more fun to come.

He looked to the side and saw a person standing near the Whomping Willow. The pointed hat was outlined in the moonlight, and a cloak covered his body. His face was not visible, but he knew who it was just by looking at his posture.

Professor McGonagall is on duty tonight. Dumbledore start of the semester, but has been too busy to be seen since.

Regulus glanced in the direction of the shed.

The Restraints Magic that Dumbledore had set up, along with those chains, looked quite sturdy, and indeed they were quite sturdy.

No matter how much the Werewolf struggled, he would only exhaust himself and wouldn't be able to break free even a little. There was really no need for the professor to stand guard over Lupin all night.

He looked down at the grass and saw James already beckoning the other two to crawl under the tree.

The chains might hold back the Werewolf, but they couldn't stop the friends' enthusiasm. If they joined forces to loosen the chains, Hogwarts would become quite a scene. The professor, who was stationed there, would most likely have to guard against them making things worse.

The pointed hat under the tree suddenly turned and faced the Astronomy Tower.

Regulus nodded in acknowledgment, but McGonagall remained gazing at the top of the tower, her cloak billowing in the wind, her shoulders held perfectly straight.

The eyes were too far away to see clearly, but the sternness in their gaze was palpable.

Regulus took a step out from the crenellation, lost his footing, and plummeted down the tower wall.

Stone windows swept past me one after another, the wind rushed up my face, and my school uniform flipped up behind me.

As it approached the ground, Levitation Charm supported its body, turning its descent into a rapid forward sweep, flying close to the ground, with the tips of the grass bending to the sides, and its black robe unfurling behind it.

Upon reaching the edge of the tree's shadow, I slowed down, my boots touched the grass, and the hem of my shirt trailed down past my calves.

Regulus straightened his collar, walked up to McGonagall, and appeared completely at ease.

I've completed my holiday homework, submitted it when school started, and completed all the papers assigned by the professor. I'm very confident.

He gave a polite bow, his voice natural. "Good evening, Professor."

McGonagall clasped her hands in front of her, her gaze behind her glasses fixed seriously on his face, and she pursed her lips. "It's curfew, Mr. Black."

Regulus looked down at the Whomping Willow, where the last piece of his robe had just disappeared into the entrance.

He turned back, his expression serious and his attitude respectful. "I'm worried he'll get into trouble, Professor."

McGonagall raised an eyebrow, followed his gaze, and then looked back at his face. "Mr. Black, if you're worried about others breaking school rules, you should include yourself in that worry too."

"It was my oversight, Professor."

Regulus bowed his head slightly, readily acknowledging the situation, then raised his head again and remained obediently in place.

McGonagall looked at him for a moment.

His attitude has always been good, and he always seems to listen. However, he still goes out in the middle of the night, just like last year and this year. Now he submits his homework on time, and he probably thinks he has made progress.

She looked away and gazed at the entrance to the tunnel, ignoring him completely. Since she was already here, she couldn't very well send him back.

Regulus took a half step to the side and stood next to the professor.

The criticism has been accepted; now we can move on to Sirius.

A roar came from the direction of the shed. It started low, but then suddenly rose in pitch, sounding distorted with pain.

Thin clouds drifted past under the moon, dimming the light under the trees. McGonagall's brow furrowed slightly, a hint of pity in his eyes. Only after the roar subsided did he slowly withdraw his gaze.

Regulus watched for a moment, his heart unmoved.

As a gust of wind rustled through the treetops, he continued, "Sirius's Transfiguration have improved again during his vacation, but when he encounters something new, he still prefers to rush forward."

Mentioning Transfiguration, McGonagall's expression softened. "If he put in the effort, and if he could just say less to Mr. Potter in class—"

The first part was fine, but when she got to the second part, her lips curled up again. "--You can improve even faster."

Black was relatively focused, but Potter sat down next to him, and the two heads were close together. Reminding him several times didn't help for long.

Regulus's eyes crinkled with amusement. "I set up a scenario for him during the holidays. At first, he was eager to get started, but later he became more willing to think of ways to do it. We can try it out again after school starts to solidify his skills."

McGonagall turned her head and glanced at him.

Worried that Sirius would cause trouble, so they came down specifically to give him some trouble?

Her hands were still folded in front of her, maintaining her professorial posture, but her tone held a hint of interest. "What are you planning to do?"

"Add another door to the tunnel," Regulus said casually, looking towards the entrance. "Stop something behind the door, put up a warning sign, and if he's willing to turn back, this is it for tonight."

McGonagall looked towards the tree roots, and her eyes behind her glasses brightened.

Potter led the way, with Black following, when they suddenly came across a door with a warning sign. The two of them were definitely more and more tempted to go inside.

She could almost picture Potter's expression when he found the door—eyes lighting up, legs moving faster than his brain—and Black wouldn't have fared any better.

"Make sure the warning is clear," she said solemnly, "So that Mr. Potter and Mr. Black don't come back and say that nobody warned them at all."

Regulus turned his head; the professor was looking into the tunnel, his expression very serious.

He deserved the same earnest reply, "Of course, Professor."

McGonagall stepped aside to give him room to maneuver and turned to look at him.

Regulus stepped forward, raised his right hand, and Magic Power gathered along his arm into his palm, his senses extending deeper into the tunnel.

The three guys had already gone inside. James was in the lead, the light from the tip of his cane illuminating the way ahead. Sirius followed half a step behind him, Peter lagged behind, dragging his feet.

There was another winding passage ahead, enough for him to make his move.

Regulus slowly opened his palm, Magic Power seeping into his feet and spreading forward along the soil.

At the underground corner, the earthen wall caves in to the side, stones are turned out and embedded in the newly formed wall, the side passage extends deeper, the ground solidifies into stone slabs, and the stones at the end are piled up to form an old stone arch.

The door frame narrows from both sides, with a thick slab of earth rising in the middle, and the surface gradually covered with bronze.

Intricate patterns and engravings emerged on the door panels, with curved lines winding around several sharp-angled patterns, intersecting and covering both doors. Dark Deposits was embedded in the grooves, making it look like an old object from hundreds of years ago.

Those patterns have no meaning, but when put together, they do look somewhat convincing.

McGonagall observed the changes underground, tilting her head slightly as her gaze followed the formation of the passage downwards.

Regulus noticed her expression, and with his other hand he swept it in front of him. The moisture in the air gathered, and tiny water droplets joined together, forming a water surface more than half a person's height.

The water rippled slightly, revealing a fork in the road and a bronze gate, next to which was the original tunnel. A glimmer of light could be seen swaying forward at the corner.

McGonagall gave him an approving look, her posture remaining upright, before quickly returning her gaze to the water.

Regulus chuckled inwardly. The professor enjoyed watching the spectacle, of course; she was Gryffindor, after all.

He continued to age the door, dust settling into the cracks in the stone, wear marks on the hinges, and the seal across the door breaking in two, its curled edges revealing a warning.

During the sealing period, it should not be exposed to strangers.

The handwriting was crooked, dark brown, with long strokes and blackened edges; it didn't look like a good thing.

McGonagall examined it carefully, her brow furrowing slightly as her gaze settled on the stone archway beneath it. "The doorframe is worn down like this, but the threshold is still new, Mr. Black. The aging process needs to be complete."

She commented in the tone of someone critiquing a piece of work. "The middle should be worn down a bit, and the edges should show some damage. The door frame has been used for as many years as the threshold."

Regulus looked at the spot she pointed to and said sincerely, "No wonder you're a professor."

McGonagall nodded reservedly, her gaze still fixed on the water, waiting for him to make a change.

Regulus moved his fingers, grinding a sunken arc into the center of the threshold, and chipping off a corner near the edge, with fine dust accumulating in the broken edge.

The professor's eyes showed a hint of satisfaction. He glanced behind the door again and continued to instruct, "If something was really locked up, there should always be some trace left inside. Mr. Black probably wouldn't find just a piece of paper on the door interesting enough."

Her eyebrows lifted slightly.

These three energetic little ones, who usually search for secrets everywhere, have stumbled upon one tonight with a seal on it. Let's see how many words of the warning they can actually read.

Regulus readily agreed and lengthened the space behind the door.

Stone pillars rise along both sides, and tall mirrors are erected between the pillars. The mirror frames have turned from dark to patina, and copper buckles protrude from the four corners to hold down the mirror surface.

Thin copper strips extend from the bottom of the mirror frame down to the ground, connecting with each other and finally converging on a closed ring deep within the Stone Hall.

A black cloth hung down, partially obscuring the mirror, and old drag marks were visible on the floor.

McGonagall looked at the fastener, her lips slightly pursed, her head tilted to the other side, her gaze shifting back and forth between the corner of the mirror and the Stone Platform.

After a moment, she raised a finger and pointed to the frame. "The fasteners should face inwards, and the things inside should be pushed outwards; the marks left by the force should also face outwards."

Regulus flipped the copper clasp over so that it would fasten to the inner edge of the mirror, and then pulled one of the clasps outwards.

He added sincerely, "The professor has thought of everything."

McGonagall's eyes lit up as she looked at the curved brass buckle. She was about to smile when she quickly stopped herself and looked at the other mirror.

Regulus's hands continued moving.

The professor, having traveled Dumbledore and experienced the Grindelwald era, has seen a great deal and his suggestions are becoming increasingly specific.

He glanced at the professor out of the corner of his eye and noticed the excitement in her eyes, then quickly looked away, pretending not to see it.

Another layer of dust was added, covering the ground, and the mirror surface was also covered with fine dust.

Regulus stopped, and the Stone Hall in the water sank into darkness, while the light on the other side was almost around the corner.

McGonagall looked at the arrangement and gave him an approving look.

Regulus placed his palm on his chest and gave her a slightly exaggerated bow.

McGonagall had already turned back to look at the water and ignored him.

Inside the tunnel, James walked forward, wand in hand, the Lumos casting flickering shadows on the earthen walls.

He turned around and shouted, "Hurry up, hurry up! Remus must be getting impatient. He said we were late last time."

Sirius, hands in his pockets in the tunnel, maintained his nonchalant air. "What's the rush? Are you afraid he'll run away?"

James turned back and continued crouching low, "If you run away, I'll bite you first."

Sirius curled his lip in disdain. "Tch."

James suddenly stopped. There was a fork in the earthen wall ahead, dark and gloomy, leading him to the side.

He paused for a moment, then turned to look at Sirius, his surprise quickly turning to excitement. "When did this new road appear here?"

Sirius peeked out from beside him, his eyes lighting up before he narrowed them.

Last time, this was just an earthen wall, and the time before that, and the time before that too. How many times had they walked through here? Why did a new path suddenly appear tonight?

James stretched out his wand and illuminated the stone embedded in the corner of the wall, with a small patch of dark green reflection in the distance.

Sirius drew his wand and cast the Lumos. As the Magic Power increased, light spread along the passage, revealing the seams of the stone slabs one by one, until a stone arch appeared at the end.

The two Bronze Door were tightly closed, their surfaces covered with patterns. A strip of paper across the middle was dark in color and too far away to read the words.

James glanced at the door, then at Sirius, raising an eyebrow.

They haven't even explored all the hidden places in Hogwarts yet, and tonight they've stumbled upon another one.