Full summary:

"For a long time, it was assumed that Salazar Slytherin was an only child but recent studies conducted by Mops et al. (1941) proved that he had at least one sibling, potentially a sister, whose first name remains unknown but who is believed having married under the name of Selwyn"

Campbell, M. (1942). A Tormented Wizard: Life and Death of Salazar Slytherin. Perpignan: Beauxbatons Academy Press.

Or how Tom Riddle's thirst for power brings him to marry that girl.

I don't own any of the Harry Potter characters.

This story contains references to sexism and racism towards non-magical beings. The author strongly condemns any form of racism, sexism, homophobia, transphobia, ablism and other forms of discrimination against unprivileged groups.

Author's note:

Hello lovely people and welcome to this fic. Here is a little contribution to the Harry Potter's fandom. After months/years of working on this but keeping it for myself, I finally decided to publish it. English is not my native language and I don't have a beta reader so please bear with me. Also, I am always extremely grateful to receive some feedback, even with nothing but a smiley to let me know whether you liked it. This fic will be a long fic and I try to update on a weekly basis :)

- Enjoy -

September 1938: Mr. Know-It-All

Tom Marvolo Riddle remembered everyone's name.

It could look like a blessing, truly it was a curse. Tom Marvolo Riddle remembered everyone's name not because he wanted to, but because his brain had the horrid tendency to store every single piece of information he encountered within one day. Such incredible memory was only bearable for it obeyed a strict and meticulous ordering process. Since the beginning of his very existence, Tom Marvolo Riddle used to sort out the people he met, hierarchically, from higher to lesser importance. The top of the list was recently occupied by the teaching staff of Hogwarts, headmaster included. He had mentally ranked them from the disciplines he liked the most to the ones he associated with plain boredom. Then came the people from the Ministry of Magic. He had never met any but he assumed they were eminent people who deserved to be treated with high regards. Fellow Slytherins came third, starting with the head prefect. He was initially ignorant of how to deal with the other houses but after a few days of field research, he came to the conclusion that the blue and silvers were by far the smartest ones. Now, he was unsure whether the Hufflepuff came before or after the house elves. It was a dilemma that he was still trying to solve but he tried not to give it too much thought for he only had a limited amount of time to dedicate to such trivial considerations.

Tom Marvolo Riddle reached the library, which was packed. He wondered whether the people would still show such diligence once the motivation of the start would begin to fade…. Regardless whether they were muggles or wizards, he had already come to the conclusion that students of all sorts showed similar mastering in the art of slacking off and procrastinating.

He squinted, his eyes scanning the room in search of an empty spot. He found one next to a brown-haired girl and he walked decisively in her direction. He cleared his throat once he stood next to her. She shot him a glance, her face jaded when he asked whether she would be so kind as to make some room him. He had half-expected her to sneer at the deferential way he addressed her but she simply held his gaze for a while before she reached for her bag that lied on the chair next to her. She dropped it at her feet and returned to her paper.

Her name was Annabel Selwyn, that much he knew.

The old clock above the entrance door indicated six thirty and nothing but the soft sound of turned pages could be heard. The room was still, immersed in utmost concentration. Yet, when the sky turned pink and the sun began to cast its burning shades of orange on the dusty bookshelves, the library emptied to the exception of a few students. Annabel was rushing, her hand swiftly moving on the parchment as if the sunset had sounded the death knell of study time. She shot sharp looks at the boy sitting next to her, vexed by his insistent gaze. She despised copycats. He was frowning, obviously unaware of her irate glances, his fingers skilfully playing with the quill he was holding.

"You made a mistake"

She paused, taken aback by his words.

For a second, Annabel thought she had misheard.

"You wrote five but it is four. Four Valerian sprigs"

With raised eyebrows, she glanced at the allegedly wrong number that he was referring to with a tilt of the head. She frowned, stunned by the sharp contrast between his precedent deference and his sudden incivility. Her eyes narrowed as she seriously considered telling him to mind his own business.

He pursued, oblivious of her evident reluctance to strike up a conversation with him.

"Three would make the potion too weak. It would cause a brief doze, at best… Five is not incorrect per se but it would give the potion a foul smell"

"Oh, I'm sorry. Are you an expert of potion-brewing? Because I am pretty sure five is accurate"

She gave him a pointed glance and he shook his head very slowly, as if she couldn't be more wrong.

"The Valerian plant has a peculiar odour. I bet that you wouldn't find anyone agreeing to drink a potion with such rancid smell. Four sprigs would bring the right state of drowse while remaining entirely drinkable"

His tone was unequivocal and he seemed very pleased with himself. It made Annabel want to slap that smug look off of that boy's face but she was a lady and her parents had raised her right.

The girl stood and she mustered all the disdain she could find within her soul as she shot him a murderous glance.

"Well, I suppose we will find out the truth soon enough, Tom Riddle"

"The potion of Sleeping Draught induces a sudden and temporary sleep…"

Annabel Sybil Selwyn's eyes wandered to the grandfather clock located behind the desk. She repressed a yawn. Only a few more minutes and she would be allowed to leave the dungeon. Surely she did not need a sleeping concoction to fall into Moprheus' arms, exhausted as she was… She had stayed up late every evening of the week to recheck what the dark-haired boy had told her at the library. She had searched in each book she owned but her investigation had proved to be fruitless, to the exception of a basic rule of thumb that seemed to govern the art of brewing potion. After hours of research, she had resolved to leave her answer unchanged and when she had handed in her assignment a few days ago, she had simply annotated her work with an update as for her new considerations.

She was brusquely jolted out of her torpor when she heard the Potion Master pronouncing her name. The man standing on the dais adjusted his tweed jacket before he bent forward, reaching for a pile of parchments on his desk. He licked his upper lip as he flipped a couple of pages, discarding the first copies on the wooden furniture.

"Miss Selwyn, how many Valerian twigs are needed for the Sleeping Draught?"

She chewed her lip nervously and flattened the folds of her pleated skirt with her palm.

"Five sir"

The wizard gave her an indulgent smile.

"Mr Riddle, how many Valerian twigs are necessary for such potion?"

"Four, Professor"

Annabel could see his face in the corner of her eyes. She witnessed him pressing his lips tight in what she believed was an attempt to repress a victorious smile. That arrogant prick… She remembered the scornful look he had given her a few weeks ago, after her name had been called right after his, once the Sorting Hat had shouted "Ravenclaw" within the Great Hall.

"And why is that, Mr Riddle?"

"It would alter the smell of the beverage Professor"

"That is correct"

Her cheeks burned in shame and she could hear the chuckles in her back, rekindling the crushing memory of her first day in Hogwarts.

The boy glimpsed at her with a feigned indifference. He noticed her tightened jaw, how she was seemingly on the brink of tears. He assumed she was proud and that reminded him of the Sorting Ceremony, how she had kept her chin up under the boos of the Slytherins. He had not understood what that fuss was all about then, until a fifth year hinted in a sigh to the increasing loss of pure bloods to other houses.

The Potion Master silenced the room with a gesture of the hand.

"I hear you, I hear you, Mr Riddle is right indeed"

The professor winked at the Slytherin boy in a knowing look.

"Yet… Miss Selwyn wrote something that is worth reflecting on… Miss, would you mind if I read an extract of your homework to the class?"

Annabel's eyes widened. Was he about to humiliate her? Courageously, she shook her head, her hands discreetly gripping at the table in front of her.

"Just as sugar neutralises sourness, the use of other ingredients to fix a badly concocted potion is often possible…"

Silence settled over the audience.

"What ingredient would you use to fix the overdose of Valerian, Miss Selwyn?"

"Lavender, Professor?"

The man on the dais shot her a curious glance and his lips parted in a warm, cheerful smile while he nodded.

And just like that, Tom Marvolo Riddle learned something else about Annabel Selwyn.

She was good at mending things.