The top of the Astronomy Tower. Regulus stood at the edge, robes plastered flat against his body.

Below, most of the castle’s lights had gone out. A handful of windows still glowed, probably upper-years grinding through essays, or some professor working late.

He glanced down.

Near the castle’s side entrance, several figures crept out in a crouch, hugging the wall for a stretch before breaking into a run across the lawn.

Too far to make out faces, but each had a distinctive silhouette and stride.

The one in front ran like he owned the place. James Potter. The boy managed to make running look arrogant.

Right behind him, loose-limbed and unhurried, hands shoved in his robe pockets. Sirius. He refused to take his hands out even while running.

Behind them, one who already looked exhausted. Heavy footfalls, shoulders sagging. Lupin. Hadn’t even transformed yet and already looked like this.

Last, one who ran two steps, looked back, ran two more, looked back again. Head swiveling faster than his legs moved. Peter Pettigrew, like an owl on legs.

Convenient timing. He’d come out in the middle of the night to work on something, and so had they.

Of course they’d be out now. Every full moon, same routine. The moon, the Whomping Willow, the Shrieking Shack. Clockwork.

Friendship and adventure. A young wizard’s two favorite things.

Regulus looked away, the corner of his mouth twitching.

He peered over the edge. Tower to ground, roughly seventy or eighty meters. Night wind blasting in from the side, snapping his robes.

One step forward, off the edge. The Flight Spell caught him, and he drifted outward, swaying gently.

The Forbidden Forest’s edge drew closer.

He touched down on the grass at the forest’s edge. Frost crunched under his feet.

No one around.

The four Gryffindors were long gone. The area near the Whomping Willow was pitch black, no figures visible. They’d already gone in.

At this hour, any normal young wizard would be asleep.

He should be asleep too. He didn’t feel like it.

His mouth twisted in a half-smile.

He crossed the lawn toward the Forbidden Forest.

At the forest’s edge, past the boundary of the Anti-Apparition Charm’s coverage, he felt the line.

Sharp and unmistakable. The border between castle space and natural space.

The castle’s side was dense, willful, carrying an ancient presence, like a silent giant watching his every move.

The giant said nothing. Took no stance. But its existence alone was pressure. Everything he did under that gaze, it watched. Only watched.

On the forest’s side, space was open. Free. Space was space, same as the Cornwall cliffs. No will, no temperament.

He stopped at the forest’s edge and tested.

Right hand up, magic pushing outward from his fingertips. Anchor set at his feet, outside the castle, at the forest’s edge.

Anchor stable. This end was fine. He pushed the other end toward the castle.

Protective will filled the channel. Spatial folding engaged, riding alongside the magic, pressing toward that boundary line.

At the border, the anchor went through. The castle’s space accepted it.

Anchors fixed spatial coordinates. They marked positions without altering the space’s own properties. The castle didn’t object to that.

But the instant the protective will reached the boundary, resistance hit. The castle’s space stripped it away.

Nothing visible. But the perception was crystal clear.

The protective will was wrapped around the passage, a silver-white layer that stabilized it, secured it, made anyone passing through feel protected.

That silver-white layer, the moment it touched the castle space’s boundary, was scraped off.

No force. No impact. No confrontation. It was scraped away, like wind blowing dust from a surface.

The protective will peeled from the passage walls, dissolving into fine silver particles that drifted briefly through the air and went out.

The passage’s skeleton remained. The spatial fold’s structure still held, geometrically continuous from the forest end to the castle end.

But without the protective will sheathing it, the passage’s interior walls were bare. Raw folded space, exposed.

It lasted less than a tenth of a second. The interior walls began to tremble. Without reinforcement, the space’s natural elasticity snapped back.

The castle end collapsed first. The folded surface curled inward from the edges, like a crumpled sheet of paper uncrumpling itself.

Then the entire passage disintegrated from that end, section by section, crumbling back toward the boundary. When it reached the border, the forest end couldn’t hold either.

The anchor in his hand cracked. Shattered.

Silver motes scattered through the air, drifted twice, and vanished.

He shook out his fingers. Tingling.

Different approach, then.

Set the castle end as a receiving anchor. Receive only, don’t project. The forest end would actively fold toward it, docking against the castle space’s edge.

In theory, the receiving end didn’t need protective will to sustain it. It only needed an anchor marking a coordinate. The passage would originate from this end, and all the structural support would stay on this side.

He pushed through. The castle’s space gave nothing back.

The anchor’s coordinate signal entered. The folded spatial surface reached the castle boundary and met... a wall.

Not hard. Not springy. It was nothing. It didn’t move, didn’t cooperate, didn’t respond.

Total silence. Not a ripple.

He pulled back. No more attempts. This matched his expectations.

Anchors could be placed inside the castle. Space Warp worked. The Spatial Network functioned. Within the castle’s boundaries, every spatial technique operated normally.

Because those techniques used the structure of space itself. No will involved.

Folding, anchoring, Spatial Transfiguration, networking. All technical operations performed on space. The castle allowed them.

Anchors worked because anchors were tools. Passages didn’t, because passages were extensions of will.

Will alone was blocked.

The castle was the castle. No matter how bright, warm, or good-hearted he was, the castle didn’t give him the time of day.

He dispersed the residual magic and flexed his fingers.

Fine. Can’t, then can’t.

Outside the castle, passages worked. Inside, they didn’t. Noted. Deal with it later.

It wasn’t as though he urgently needed to open doors inside the castle. If he ever needed to run, Fiendfyre flight would do.

Someday, though, he’d crack it. Open passages all over the castle. Bathroom door straight into the headmaster’s office.

Regulus stood on the boundary line. Castle on one side, Forbidden Forest on the other.

He exhaled. White breath curled from his mouth and dissolved in the moonlight.

The moon stretched his shadow long, casting it across the dead grass all the way to the roots of the first row of trees.

The forest was quiet. Wind swept through the treetops, a brief rustle, then silence.

Then he felt it. Distant, dozens of meters away. Someone standing there. No telling how long.

He turned.

Beside the old oak, Professor McGonagall stood wrapped in a dark cloak, her pointed hat tracing a sharp outline in the moonlight.

Too far to read her expression, but that posture alone was terrifyingly stern, the kind that made a person reflexively review whether they’d done something wrong.

Regulus frowned slightly.

Again. The professor had clearly been standing there for some time, but she’d only let him notice after he’d finished.

Being talented is really something, isn’t it?

Whatever he’d been doing, she’d probably seen all of it.

But then again, it was spatial magic. McGonagall had taught him Spatial Transfiguration herself.

Spatial passages, if you stretched the definition toward Spatial Transfiguration, held up. No contradictions.

Let her see.

He adjusted his expression, straightened his robes, and walked toward her.

A few dozen meters. He didn’t rush, but half a minute was plenty. By the time he reached her, he’d settled into a posture of polite composure.

Up close, he read her expression.

Eyes sharp behind the spectacles, lips pressed into a thin line. Thoroughly serious.

He stopped three or four meters away and inclined his head.

"Mr. Black." McGonagall’s voice cut clean through the night wind. "Curfew is in effect."

Regulus was the picture of respect. A courteous nod, tone even, not a trace of guilt. "Professor."

McGonagall studied him for a long moment.

She wasn’t the least bit surprised to find Regulus Black at the edge of the Forbidden Forest at this hour.

She didn’t treat him like an ordinary student. She knew what this boy was.

Prowling the forest at night would be reckless mischief from anyone else. From him, it was probably something purposeful.

But she was the strictest Head of House in all of Hogwarts, and a student out of bed past curfew was a student out of bed past curfew, regardless of who they were.

Displeasure didn’t mean punishment. Still, the proper attitude had to be shown.

She held her gaze until Regulus lowered his head slightly. Then she looked away. No questions about what he’d been doing. No points deducted.

Her gaze drifted past him toward the Whomping Willow in the distance.

Under the moonlight, its branches swayed gently. The tunnel entrance at the base was faintly visible.

The figures had gone in long ago. Only their footprints remained on the lawn.

Regulus looked the same direction.

Neither of them spoke.

After a while, she spoke. "Sirius’s transfiguration has been progressing quickly."

Her tone had shifted. The sternness was put away, her voice softening a fraction.

The corner of Regulus’s mouth curved.

If McGonagall said so, the progress must be real. Funny that Sirius had never bragged about it to him.

In the beginning, Sirius had wanted to get stronger because Regulus had beaten him.

Later, there’d been a conversation between them. Strength and choices. A few words exchanged.

After that, Sirius had found his own path in transfiguration.

Now, maybe it was about showing off. About wanting to win. Maybe something else entirely.

Whatever the reason, a kid willing to push himself was enough.

"Thank you for looking after Sirius."

The words came out naturally, carrying a note of gratitude he probably hadn’t intended to show, but it was there the moment they landed.

McGonagall turned, caught his expression, and a flicker of amusement crossed her face. The corner of her mouth lifted, barely, gone in a blink.

Regulus looked up at her. "Professor, tonight it’s you who’s..."

He glanced toward the Whomping Willow, letting the sentence trail off.

McGonagall was quiet for a moment. A slight shake of her head, tone flat. "Albus isn’t here."

Confirmation settled in his mind.

On full-moon nights, Dumbledore was supposed to be watching over this. McGonagall was covering.

"Has Professor Dumbledore been busy lately?" He asked it casually, like small talk.

McGonagall turned to look at him. Behind the lenses, her eyes were bright and sharp.

Regulus met her gaze, brow furrowed slightly, expression open.

McGonagall didn’t address the look on his face. Didn’t address whatever he was fishing for. Probably wasn’t planning to call him out on it, same as she hadn’t questioned whatever spatial magic he’d been doing.

She looked away from him, back toward the Whomping Willow.

"He asked me to pass along a message." No emotion in her voice. A relay, nothing more. "If you need to find him, you know how."

Regulus stood beside her and nodded.

Fawkes.

The phoenix tail feather Dumbledore had given him. Kept on his person at all times, never used.

In an emergency, it could summon Fawkes. Phoenix flame transport, instant extraction from any situation.

Now the feather carried an additional meaning.

Dumbledore wasn’t at Hogwarts, but the channel remained open. He could reach the old man whenever he needed to.

Regulus inclined his head. "Understood. Thank you, Professor."

McGonagall nodded, nothing more.

Her gaze lingered on him a moment longer, then withdrew.

"Go to bed, Mr. Black."

The sternness was back. Proper Head of House tone.

Regulus didn’t hesitate. "Good night, Professor."

He turned toward the castle and walked. A few steps in, he looked back.

McGonagall still stood beside the old oak, facing the Whomping Willow.

He turned away and kept walking.

Baruk poked his head from the inner pocket, eight eyes glancing toward the professor, then up at Regulus’s chin. A single click.

"It’s fine. Extra rations tonight."