On September 1st, 1972, at 10:47 AM, Regulus Black stopped in front of the wall between Platforms 9 and 10 at King's Cross Station.
The eleven-year-old boy was slender, wearing a neatly pressed dark green robe with a House of Black family crest brooch pinned to his collar.
His hair was pure black, with the House of Black's signature slight curl, and his grey eyes calmly scanned his surroundings.
In his left hand, he carried a brand-new Dragonhide trunk—Walburga had insisted on the most expensive one—and in his right, a cage containing a Snowy owl.
The owl in the cage stood quietly, its amber eyes observing the surroundings through the bars; unlike other owls, it didn't flap its wings anxiously, only turning its head occasionally.
Regulus took a deep breath.
Through this wall lay another world, one he had read about in books for ten years and was about to step into personally.
He stepped forward, the sensation like passing through a warm mist, and then sound flooded in.
It was a noise full of life and chaos: the hooting of owls interwoven into a discordant chorus, and cats letting out dissatisfied mews from their baskets.
Screams triggered by toads jumping out of unfastened pockets, parents giving last-minute instructions, and children's voices cracking with excitement.
Platform 9 3/4.
The Hogwarts Express lay on the tracks like a crimson beast, its engine belching white steam that condensed into rolling clouds under the platform roof.
Students surged toward the carriage doors like a tide, their colorful robes merging into flowing blocks of color.
Regulus stood in place, his gaze calmly sweeping across the platform.
He saw the Potters; Charlus and Euphemia Potter stood not far away, wearing the gentle smiles typical of parents sending their child to school.
Four people were gathered around them.
James Potter stood at the front, his brown hair as messy as if it had just been swept by a hurricane, his glasses perched crookedly on the bridge of his nose.
He was waving his arms, demonstrating some exaggerated movement to a thin boy carrying a worn trunk—that was Remus Lupin.
Peter Pettigrew stood half a step behind James, short and round-faced, his eyes constantly darting around.
Sirius Black leaned against some luggage.
At thirteen, he was another head taller than last summer, his shoulders beginning to show the silhouette of a teenager.
He wore those Muggle jeans Walburga utterly detested, washed until they were pale with wear at the knees; on top was a plain dark shirt, with a Gryffindor school robe draped loosely over it.
The robe had clearly been modified; the silver trim at the collar had been dyed gold-red, and there were traces of an embroidered lion on the cuffs.
James said something, and he threw his head back and laughed—a truly relaxed laugh from deep within his chest—one hand resting on Remus's shoulder, the other gesturing.
Then his gaze swept across the platform and saw Regulus, his laughter naturally subsiding.
He didn't look away, but he didn't nod or acknowledge him either; he just watched quietly across twenty feet of distance, through the noisy crowd.
Then James saw him too.
"Hey!" James shouted, his voice clear even amidst the platform's clamor. "Look who it is! Has the Black Family's little viper come early to get used to the environment?"
The shout drew the attention of other students and parents; for a moment, many eyes turned toward him.
Sirius's hand pressed on James's shoulder—the movement was light, but James immediately shut his mouth. Sirius didn't speak, only shook his head, then turned to pull open the carriage door and was the first to board the train.
James followed, with Remus and Peter close behind; before boarding, James glanced back at Regulus, a mix of curiosity and hostility in his eyes.
Regulus picked up his trunk and walked toward the middle of the train; James Potter was not worth bothering with.
The interior of the Hogwarts Express was more spacious than it looked from the outside, a typical application of the Undetectable Extension Charm.
The corridor was carpeted in dark red, with sliding doors on both sides, most of which were already closed, voices and laughter drifting from within.
Regulus walked quietly down the corridor.
Passing the third carriage, the door was open, and he caught a glimpse of the scene inside: James had already taken off his jacket and was trying to stick Chocolate Frog cards to the ceiling.
Peter was hunched over, fiddling with his luggage, while Remus sat by the window, holding a worn copy of History of Magic.
Sirius sat opposite him, legs propped on the empty seat, toying with a Golden Snitch model he had acquired from who-knows-where.
Sirius looked up, his gaze passing through the open door and meeting Regulus's.
Then Sirius looked down and continued to fiddle with the Snitch, as if he had seen nothing.
Regulus continued walking forward.
After passing a few more carriages, most of which were full, he saw two people near the seventh carriage.
A red-haired girl with green eyes and faint freckles on her face; she wore a simple black robe, but it was very clean, with a simple silver brooch pinned to her collar—Lily Evans, second year.
Beside her was a black-haired boy with greasy hair and a sallow complexion; his robe was clearly a second-hand one that had been altered to fit, with worn cuffs—Severus Snape, also a second year.
The two were talking in low voices; Snape leaned forward as he spoke, his speech rapid, fingers occasionally tracing patterns in the air. Lily listened intently, nodding occasionally.
As Regulus passed, Snape looked up and glanced at him.
Then he saw the trunk in Regulus's hand, the Snowy owl in the cage, and the well-tailored, expensive dark green traveling robe Regulus was wearing.
His lips tightened slightly, and a mix of hostility and wariness flashed in his eyes.
Then he looked away and continued talking to Lily.
Regulus reached the ninth carriage, which was empty.
He put his trunk on the luggage rack, placed the owl cage under the opposite seat, and sat down, taking a notebook from his robes.
He found the most recently written page: The Relationship Between Ancient Rune Variants and Magic Flow Efficiency.
Below was a series of complex symbols, formulas, and diagrams; some were standard Ancient Runes, but most were variants he had modified, simplifying strokes and optimizing magic conduction paths.
He took out his quill, dipped it in ink, and began to record his thoughts from the previous night.
The train pulled out of the London suburbs, the scenery outside changing from dense buildings to scattered farmhouses; it was a stretch of rolling fields, the sky gloomy and the clouds hanging low, as if it were about to rain.
The carriage door was suddenly pulled open, hitting the wall with a dull thud.
Regulus looked up after completing a complex curve.
Actually, he didn't need to look; he had sensed who it was even while the person was still outside the door.
"Look who it is!" James Potter's voice was full of performative exaggeration. "The little young master of the Black Family, studying Dark Arts here all by himself?"
Regulus didn't react, just watched his performance quietly.
Although James Potter was already in his second year, to him, he was no different from a small child.
James walked into the carriage, followed by Remus and Peter; Remus's expression was somewhat uneasy, while Peter gripped the doorframe nervously, as if ready to run at any moment.
"I'm talking to you!" James walked up to Regulus and leaned over to stare at him, his tone aggressive. "I heard you always bully Sirius at home? Playing the good kid to steal all the attention?"
"James," Remus's voice was low, "don't."
"Don't what?" James straightened up, his hand already reaching for the wand in his inner robe pocket.
Regulus only found it amusing; he wondered how Sirius had described him to his friends, that they actually thought he bullied him.
"James!"
Sirius's voice came from the corridor; he appeared at the door, his breathing slightly uneven.
He said to James, "I told you not to come."
"I'm just looking!" James said defiantly. "He's not going to eat anyone—"
Just then, two more people ran over.
It was Lily Evans and Severus Snape.
Snape glanced at the situation inside the carriage, a mocking curl appearing on his lips. "How lively. Potter bullying a freshman again?"
James spun around. "None of your business, Snivellus!"
Then he saw Lily Evans behind him, his tone becoming even worse: "You again, meddling Evans."
Snape's face instantly darkened, and his hand also reached for his wand.
Lily held him back. "Severus, don't!"
But James was faster: "Expelliarmus!"
A jet of red light shot toward Snape.
The carriage was narrow, and the two were less than ten feet apart; the spell reached Snape almost instantly.
The wand automatically slid into Regulus's left hand; he gave it only a slight wave, relaxed and effortless, without any violent movement.
But the spell stopped, frozen in mid-air.
The red light manifested in the air; the Expelliarmus spell now looked like a glowing red ribbon, one end connected to the tip of James's wand and the other hanging half a foot in front of Snape's chest, motionless.
The entire carriage fell into a dead silence.