Chapter Text
Albus, technically, isn't doing anything wrong.
He stands in front of the door to the third study in Grimmauld Place - a room sealed with magic so ancient and stubborn that no one has managed to step inside for decades. Not even his father. Not even Harry Potter, Savior of the Wizarding World, could force his way through.
The house was just one of many properties his father inherited, weighed down by a history far too grim for polite conversation, but Albus loved it anyway.
The first time he stepped foot inside, he had thought it was macabre. He couldn't wrap his mind around how this dark, suffocating place could have ever served as the headquarters for the famous Order of the Phoenix, but it had. His father had brought him here during the Christmas holidays of his first year at Hogwarts, right on the heels of yet another exhausting argument about why ending up in Slytherin wasn't the end of the world.
The house, unlike their own home, expanded unnaturally on the inside - a labyrinth of shifting hallways where Albus has gotten lost more times than he cares to admit. That afternoon, shortly after Christmas, Harry had led him into a room as vast as their living room and kitchen combined. It was choked with decades of dust, so thick that only faint, geometric outlines on the floor hinted at where furniture used to sit. Even the dust seemed to have its own layer of dust.
Harry had taken him by the shoulders, steering him toward a blank wall. Albus was confuse - why, in the name of Merlin and Morgana both, were they staring at bare plaster? But before he could ask, his eyes caught faint, faded lettering near eye level: R-E-G-.
Albus reached out to wipe the grime away, but his father caught his wrist, fingers clamping down with sudden firmness.
"You don't need to get yourself dirty," Harry muttered, raising his hand.
With a soft rush of air, the wall cleaned itself completely. Albus held his breath - first, for the sheer casualness of his father's wandless magic. Harry Potter uses non-verbal spells around the house the way other people use cutlery, and Albus still feels that sudden, heavy press of magic in the room every single time. Second, because once the grime vanished, the name Regulus Black stared back at him. It was a family tree, painted across the entire span of the wall, tracking the lineage of the dark dynasty that had built this house.
"What you're looking at, Albus, is the family tree of the ancient and noble House of Black." Harry's voice carried a strange edge - a mix of bitter irony and something raw that Albus couldn't quite name. "As you know, this property belonged to my godfather, Sirius Black. And this is Regulus Arcturus, his younger brother."
Albus looked closely at the painted portrait of the gray-eyed boy. The gray in those eyes hit him right in the chest; they had that exact silver glint of Scorpius’s gaze. His chest tightened. He shifted his gaze, searching the sprawling branches for Sirius Black, but there was no name, no portrait - only a scorched black tear where his place should have been.
"Er- why isn't Sirius there?" Albus asked quietly.
"The Blacks were an ancient family. For five hundred years, every single one of them ended up in Slytherin. Until Sirius," his father said, letting the silence press heavy between them. "Sirius ended up in Gryffindor."
"Being a snake is different from being a lion, Dad." Albus swallowed past the lump in his throat, his eyes lingering on the portrait of the boy who looked so much like his best friend. "No one judges you if you're a Gryffindor. Everyone cheers for you. Everyone knows what the golden trio did for them." His hands tightened into fists in his pockets as he met his father's gaze. "Everyone knows who you are."
His father's green eyes - so identical to his own -darkened, turbulent and shadowed, his jaw setting tight as if he were fighting a war inside his own head to find the right words. Albus waited, the air thick enough to choke on, but Harry simply turned away. He cast one last glance at the wall - Albus could have sworn his eyes lingered on a very specific, empty spot - before stepping out of the room.
In the years that followed, Albus came back to Grimmauld Place again and again. It was disturbing, really, how the house seemed to call to him. Being a Slytherin in the Potter family was hard enough without an ancient, dark house beckoning him like he belonged to it.
But in these gloomy corridors, Albus found a strange sort of comfort he never got at home. He discovered that an ancestor of his, generations ago, had married into this family his father spoke of with such quiet disdain. He found out that Scorpius was part of this bloodline, and so was Teddy - making them second cousins. Even Aunt Andromeda, whom he’d known his whole life as a soft, kind woman, had been an integral part of this house. Slowly, Albus had begun spending more time around her than around his own father.
And now, the house that had become his refuge has called him to this specific door.
It’s absurd. Not even Harry Potter had managed to break the wards on this room. How could Albus ever hope to possess even half the magical strength of his father? He lets out a bitter sigh, stepping back to head downstairs. It’s stupid to even stand here.
Exactly, Albus. Prove once again why you’re not a lion. Too scared, too weak to even try. His own mind is always crueler than any stranger could ever be. Such a coward, little snake.
Gritting his teeth, Albus reaches out and slams his palm against the tarnished doorknob. It’s a reckless, foolish gesture - he knows he should be weaving complex unbinding charms - but then comes the sound.
A sharp, heavy sequence of metallic clicks echoes through the wood as the ancient lock disengages itself, mechanism by mechanism. Albus pulls his hand back, staring at his palm with wide, disbelieving eyes. How?
A fine tremor runs down his spine. As the final latch yields, the heavy oak door swings inward with a low creak, revealing a dark, yawning gap that makes his chest tighten with sudden, frantic excitement.
Without second-guessing himself, he slides his wand from his pocket and gives it a quick flick, whispering a soft charm. Across the room, dozens of forgotten candles spring to life, casting a warm, golden glow against the shadows. Tall, heavy velvet drapes cover the far wall, blocking what must be massive floor-to-ceiling windows.
Albus steps inside, taking a deep breath of air that hasn't moved in decades. He crosses to the windows and wrestles with the heavy fabric; dust rains down in thick, suffocating clouds, setting off a fit of sneezing that leaves his eyes watering until he manages to force the latches and shove the window open.
Fresh air and pale sunlight flood the space, revealing the study in all its quiet grandeur. What looked like a modest room from the hallway is expanded by seamless, undetectable expansion charms. To his right, a massive bookcase of dark, polished mahogany spans the entire length of the wall, packed with ancient tomes and silver trinkets. In front of it sits a heavy matching desk.
Albus moves around the desk, his heart hammering against his ribs. Since his father never managed to step foot in here, Albus is the first person in half a century to see it.
The desk features a row of small drawers, each fitted with a tarnished silver handle shaped like a coiled serpent, its eyes set with tiny, dull emeralds. Above each handle, three letters are meticulously engraved into the wood: A.R.B.
A.R.B.?
Regulus Arcturus Black? No- Regulus was R.A.B. Who was A.R.B.?
Desperate for answers, Albus reaches for the top drawer. It glides open without a sound. Inside, resting on the velvet lining, lies a single object: a diary bound in deep green leather.
The moment his eyes land on it, Albus feels the air shift. A low hum of magic radiates from the leather - intense, warm, and distinctly alive.
With shaking fingers, he lifts the diary and sinks into the leather chair behind the desk, holding his breath. His father had once warned him about magical diaries, telling him a terrifying story about a memory preserved in ink when his dad was only twelve. Opening this feels like walking onto a tightrope. He knows he should drop it, turn around, and go back downstairs to sulk in the kitchen like he always does.
But the house called him here. This room unlocked itself for him.
Albus hesitates for one last heartbeat, traces the smooth green leather, and opens the cover.
Dear diary.