Chapter Text
September 1st, 1993.
The Hogwarts Express screeched to a halt beneath the dark Scottish sky.
Steam billowed across the platform as hundreds of students poured from the scarlet train, laughing loudly after spending the entire summer apart. Owls hooted from their cages, cats darted between trunks, and anxious first years hurried after the towering figure of Rubeus Hagrid.
For everyone else, it was simply another September.
For one girl...it was the beginning of a mission over fourteen years in the making.
Agatha stood perfectly still on the platform.
Unlike the other students, she wasn't searching for familiar faces.
She had none.
Her emerald-trimmed travelling cloak concealed pristine Hogwarts robes beneath, every button fastened with military precision. One hand rested lightly atop a black leather suitcase, while the other gripped a wand carved from dark yew.
Her expression never changed.
Around her, students bumped shoulders, shouted greetings and complained about homework.
She watched.
Observed.
Catalogued.
A habit drilled into her since childhood.
"Never be the loudest person in the room.
The loud ones die first."
Barty Crouch Jr.'s voice echoed through her memory as clearly as if he stood beside her.
"Knowledge is power."
"Silence is protection."
"People reveal everything if you simply let them speak."
She had spent her entire life listening.
Watching.
Learning.
Now she was finally here.
Hogwarts.
The castle her father had once ruled through fear.
The castle where one day...Lord Voldemort would return.
But not yet.
Not until the time was right.
Professor McGonagall approached with brisk, confident steps.
"You must be Miss Sinclair."
Agatha inclined her head, "Professor."
The older witch blinked.
Her accent.
French...mostly.
But beneath it was something else.
Not quite British.
Not entirely French either.
Difficult to place.
"Welcome to Hogwarts."
"Thank you."
That was all.
No smile.
No nervous questions.
No curiosity.
Merely calm politeness.
McGonagall found herself oddly unsettled.
Most transfer students looked overwhelmed.
This girl looked...prepared.
Almost as though she'd already memorized the castle.
"Your records state you were educated by private tutors."
"Yes."
"And previously lived in France?"
"For several years."
Again...
Perfectly truthful.
Technically.
McGonagall continued walking beside her.
No hesitation.
No stumbling over the unfamiliar grounds.
She carried herself with remarkable poise for someone only fourteen years old.
Almost aristocratic.
Almost...pure-blood.
Without warning— McGonagall looked sideways and froze, for just a heartbeat.
The profile.
The curls.
The delicate nose.
No.
Surely not.
Her heart skipped.
Impossible.
Rosalind?
The thought vanished as quickly as it came.
Rosalind Sinclair had been dead for fifteen years.
Everyone knew that.
Didn't they?
Agatha noticed the lingering stare.
She filed it away mentally.
Observation 17: Professor McGonagall recognized something about my appearance. Unknown reason.
She didn't ask.
Questions created attention.
Attention created suspicion.
Suspicion got people killed.
They entered the Entrance Hall.
Portraits whispered immediately.
"A new student?"
"Mid-year?"
"No..."
"Start of term."
"She's older."
"Pretty girl."
"Very serious."
Agatha ignored every painting.
Moving staircases fascinated most newcomers.
She barely looked.
Magic was ordinary.
She had grown up surrounded by cursed objects, enchanted libraries and rooms protected by spells forgotten by most modern witches and wizards.
Hogwarts wasn't frightening.
It was...beautiful.
Old.
Ancient magic lingered within every stone.
She could almost feel it humming beneath her feet.
Older than the Ministry.
Older than her father.
Older than history.
Interesting.
Inside the Great Hall...
Conversation filled the air.
Hundreds of students.
Hundreds of voices.
Hundreds of faces.
Agatha's gaze swept across them only once.
Older students.
First years.
Teachers.
Ghosts.
House tables.
Exit routes.
Potential threats.
Potential allies.
The enchanted ceiling.
The windows.
Nothing escaped notice.
Then, she stopped.
The headmaster, Albus Dumbledore.
His blue eyes were already on her.
Watching.
Not casually.
Carefully.
He smiled kindly.
She did not return it.
Dumbledore's smile almost faltered.
The resemblance struck him like a curse.
Rosalind.
Merlin...
Even after fifteen years...
How?
No.
Calm yourself.
Coincidences exist.
Yet...his instincts, honed over more than a century, whispered otherwise.
Around the staff table, recognition spread one professor at a time.
Professor Flitwick inhaled sharply.
Pomona Sprout frowned.
Madam Hooch stared openly.
Remus Lupin...went completely still. His teacup never reached his lips.
His hands trembled almost imperceptibly.
Rosalind.
She looked exactly—
No.
Not exactly.
Rosalind's eyes had sparkled with life.
This girl's eyes looked...empty.
Not vacant, controlled.
Like frozen water.
Severus Snape's black eyes narrowed. His expression remained unreadable.
But inside...his thoughts raced.
Impossible.
The resemblance bordered on absurd.
Even Lily hadn't resembled someone this perfectly.
Had Rosalind had a younger sister?
No.
He would have known.
Wouldn't he?
Meanwhile...
At the Gryffindor table...
Harry noticed everyone on the staff platform staring.
"What are they looking at?"
Ron followed his gaze.
"...Who's that?"
Hermione adjusted her posture. "There wasn't another first year."
"No." Percy answered. "She's older."
Fred leaned sideways. "Transfer student?"
George nodded. "Haven't had one of those in ages."
Ginny looked curiously toward the entrance.
"She looks..."
She couldn't finish the sentence.
She simply looked familiar somehow, though she'd never seen the girl before.
Across the Hall...
The Slytherin table observed with equal interest.
Draco Malfoy leaned back confidently.
"French."
Pansy smiled. "How do you know?"
"The cloak."
Blaise shrugged. "And?"
"Looks expensive."
Theodore Nott quietly watched.
Unlike Draco...he noticed something else.
The new student wasn't looking around in wonder.
She was studying exits.
Teachers.
Students.
Like someone entering enemy territory.
Interesting.
Agatha felt hundreds of eyes following her.
Her heartbeat never changed.
She had been trained for this.
Large crowds.
False identities.
Eye contact.
Conversation.
Memory drills.
Etiquette.
Even handwriting.
Every part of Agatha Sinclair had been carefully manufactured long before she ever stepped foot inside Hogwarts.
The Ministry had investigated every document.
Every signature.
Every record.
Every one was authentic.
There was no Rosalind Sinclair listed as her mother.
No father.
Only two deceased guardians and years spent under private magical tutors in southern France.
A flawless lie.
One personally approved by Lord Voldemort years before his fall.
Hidden beneath that identity...was another truth.
One no living soul knew.
Not Dumbledore.
Not the Ministry.
Not even Bellatrix Lestrange locked away inside Azkaban.
She alone carried the blood of Tom Marvolo Riddle.
His daughter.
His heir.
His greatest secret.
And tonight...she would sit beneath the same roof as Harry Potter.
The boy who had unknowingly destroyed her father's body.
Agatha glanced toward him only once.
Messy black hair.
Round glasses.
Green eyes.
So ordinary.
This...was Harry Potter?
The boy the wizarding world worshipped?
She looked away almost immediately.
Father had forbidden unnecessary interest.
"Ignore Potter unless instructed otherwise."
"His time will come."
She obeyed without question.
Professor McGonagall stepped forward.
The chatter slowly faded.
"Before we begin the Sorting of our first years, Hogwarts welcomes a transfer student joining Fourth Year."
Students exchanged surprised whispers.
"A transfer?"
"From where?"
"I've never heard of that."
McGonagall continued.
"Miss Agatha Sinclair."
Silence fell over the Great Hall.
Every eye turned toward the solitary girl standing beneath the candlelit ceiling.
Agatha walked forward without hesitation.
Without nerves.
Without excitement.
Without fear.
As if she had known, long before she arrived, that one day every person in Hogwarts would be watching her.
And somewhere, deep inside the enchanted castle, the ancient Sorting Hat stirred before anyone had even lifted it.
It had felt a mind like this only once before.
Nearly fifty years ago.
And history...was about to repeat itself.