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Taming the True Fire (HP)

[OC Harry Potter fanfiction/Marauders era] Catherine McMahon is not your ordinary witch. She keeps a dark secret about her very existence, from which she tries to escape in the friendships and love she finds at Hogwarts. Exploring her heritage and growing powers, Catherine is faced with choices which could destroy her family, friends and her soul. [R18+] This is not a happy and easy to read story. There are a lot of dark, and possibly triggering, themes and topics throughout the story. In later chapters there is explicit sexual content, dominance and submission, and related alternative sexual practices. Also, most of the characters, including the OC, are very far from good, perfect people. There's a lot of emotional pain involved. I change the lore significantly, where I needed for the sake of the story I'm trying to tell, but besides that I try to stay true to the HP universe as we know it. This includes the books but also other sources such as games, the FB series, etc. You can see my visual idea of the characters, items and events from the fanfiction on https://pin.it/5CqE3zjkx All images are generated via AI.

Sailea · หนังสือและวรรณกรรม
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182 Chs

Chapter 155: Bubbling Cauldrons (3)

Catherine had always loved Potions, but even her enthusiasm wavered at the thought of two long hours in the ice-cold dungeon, where students' breaths hung like mist and mingled with the steam from bubbling cauldrons. Making the bad situation worse, Gryffindors were sharing the class with Slytherins that term. This meant the young witch was once again stuck working with Lily and Snape, as Professor Slughorn was adamant it was the best way to ensure good results—keeping her from chatting with the boys and avoiding Peter's inevitable disasters.

The young witch had to reluctantly admit that he had a point—her constant drive to compete with Snape pushed her to always perform at her best. However, this came with a fair amount of stress, as the Slytherin was genuinely hard to outshine. To make matters more challenging, Lily was also a gifted potion-maker, often coming up with unconventional solutions that impressed their professor. Surrounded by such intimidating talent, Catherine frequently found herself putting in far more effort than usual, without always ending up at the top of the class. While she didn't mind losing to Lily, being bested by Snape was another matter entirely—and it happened far too often for her liking.

When the Gryffindors arrived on Tuesday afternoon, the Slytherins were already inside. The black-haired girl sighed in exasperation and dropped her school bag under the table where Snape was sitting, scribbling something in his notebook with deep concentration. Catherine hadn't seen him since her return to Hogwarts, and she was startled by his appearance. He looked utterly dishevelled—thinner than before, his skin so pale she could make out the veins on his temples. His black hair, now reaching just below his shoulders, was so oily it clung to his head like damp seaweed. When Snape finally lifted his eyes, she noticed deep purple circles beneath them. But what shocked her most was that he didn't even bother to give her one of the disdainful looks he usually reserved just for her. The boy seemed numb, entirely detached from everything around him. Even when Lily sat down, he only cast her a fleeting glance, a vague flicker of hope in his eyes that faded instantly as the Gryffindor witch turned her head away from him.

'Is Lily still angry at him about the Halloween Ball?' – Catherine wondered. Though she hadn't witnessed Snape's outburst firsthand, she could easily imagine how hurt Lily must have been. Despite the deep hatred and the pain they had inflicted on each other over the years, the young witch felt a sense of pity. Recently, Catherine McMahon had come to the disturbing realisation that she somewhat respected Snape. He was one who never shied away from confrontation and was always prepared to face the consequences of his actions. Paired with his sharp intellect and undeniable power, he might have been someone she'd want to befriend, were it not for his insufferable arrogance and the deep-seated animosity he had shown her ever since their first encounter in Diagon Alley. Still, Snape had risen to the status of a worthy enemy in her eyes, and it irritated her to see him reduced to such a pathetic state because of Lily.

'It's no fun to beat him if he's not even trying.' – she thought, glancing up as Professor Slughorn appeared in front of the class. 

"Now, my dear students," – the Potions Master began, his belly wobbling slightly as he adjusted his velvet waistcoat - "the art of antidotes is among the most delicate branches of potion-making. Poisons can be subtle, slipping unnoticed past the untrained eye, or as blatant as basilisk venom. The secret to crafting an antidote lies in pinpointing the poison's unique properties. Some poisons, like the Draught of Living Death or Serpent's Breath, demand intricate, multi-layered remedies. Others, such as Fangrot or Noxburn, can be neutralised with something as simple as a bezoar. But beware, not all antidotes are universal. A dose of Mandrake Restorative Draught will be useless against Aconite Poison, just as a bezoar will offer no salvation from a well-brewed Midnight Shade!"

"The true challenge lies in understanding the delicate interplay of ingredients—misjudge just one, and you might aggravate the poison." – the teacher continued after a brief pause – "Subtlety and precision, my dear students, are everything. Now, for today's task, please come forward and collect a flask of common poison. You have two hours to concoct the correct antidote. And do be careful… especially you, Mr Pettigrew!"

Catherine quickly approached the teacher's desk and took a vial of bright red poison. From her initial observations, she deduced it was likely Wraith's Whisper—a particularly nasty concoction that induced hallucinations, paranoia, and confusion, eventually leading the victim into a coma. The antidote was primarily based on lethifold skin and essence of aconite, but it also required several additional ingredients that had to be prepared in advance, such as steamed dittany and foam from boiled fluxweed.

'I hope that I'll have enough time to pull this off.' – the girl thought as she swiftly set the fire under her cauldron and began working.

After an hour and a half, the young witch was drenched in sweat, her hair plastered to her forehead. The vial of poison she was meant to neutralise sat untouched, and her antidote was nowhere near complete. Across the table, Snape worked with unwavering focus, and judging by the empty space where his ingredients once were, he seemed to be nearly finished.

"Your time is almost up." – Professor Slughorn's voice echoed through the dungeon – "Once your antidote is complete, pour it into the vial containing your chosen poison, label it, and leave it aside for me to assess if the poison has been neutralised."

Catherine glared at her bubbling potion, biting her lip in frustration. There was no way it would be ready before class ended, and what she had so far was unlikely to counteract the Wraith's Whisper. Feeling a knot tighten in her chest, the Gryffindor reluctantly poured a portion of her half-finished antidote into the vial of poison. The mixture hissed and turned a murky green—far from the crystal-clear result she needed.

Sighing in resignation, she prepared to extinguish the fire beneath her cauldron, already bracing herself for her first failed grade in Potions. But then, a sudden idea struck her like lightning. Her heart raced as she glanced around to make sure no one was watching. Desperation fuelling her, Catherine opened herself to true fire and conjured a tiny, flickering golden flame. With a deep breath, she carefully dropped it into the vial.

To her astonishment, the mixture glowed and slowly turned clear. She could hardly believe it. Thanking her lucky stars, Catherine quickly labelled her vial and placed it on the edge of the table, her heart still racing.

"Weren't you brewing an antidote for Wraith's Whisper?" – Snape asked, his sharp eyes narrowing as they flicked toward the now-neutralised poison.

"Yeah. Why?" – Catherine replied defensively.

"How did you finish it so quickly?" - the Slytherin demanded, his gaze growing more intense, his black eyes squinting with suspicion.

Catherine smirked, a little thrill of satisfaction running through her. She had finally rattled him. "I thought you were the Potions genius... Figure it out."

"Oh, my!" – Slughorn's booming voice cut through the tension as he approached their table – "Catherine, my dearest girl! You've neutralised the most complex poison in the class, and in record time! Twenty points to Gryffindor! Once again, I'm astonished by the talent of Muggle-born students! Lily was also impressive as ever. Severus, you'll need to step up if you want to keep pace with these two charming brilliant ladies!"

Judging by the way Snape's lips tightened and the look he shot Catherine, "charming" was the last word on his mind. In response, the black-haired witch flashed him her brightest smile, savouring the small victory as she packed her things into her school bag.

"Your antidote was amazing, Daisy!" – Lily beamed – "I can't believe how much you've improved in Potions. At this rate, you'll be top of the class in no time!"

Catherine noticed Snape stiffen at Lily's words. For a fleeting moment, hurt flashed across his face—gone as quickly as it had appeared. Amused, the girl couldn't help but admire Lily's ability to hold a grudge when she felt wronged.

'I better make sure I never end up on her bad side.' – Catherine thought, as Lily excitedly pushed a small notebook under her nose.

"I've been working on a modification for the Moon Cycle Draught." - Lily announced with enthusiasm -"Do you think it makes sense? Madame Pomfrey said it could really help some of the girls here. Do you think I should tweak anything?"

The black-haired witch glanced from the notebook to Lily's hopeful expression, feeling a pang of guilt. She sighed deeply, slinging her schoolbag over her shoulder and heading toward the door.

"Sorry, Lils. This is a bit too complicated for me. Maybe Snape can help you."

With that, she made her way out of the dungeon, her thoughts already on dinner.

'I hope the snowfall clears up before Astronomy class tonight.' – she mused, feeling a small sense of satisfaction. She had, after all, kept the promise she'd made to herself at Slughorn's Christmas party.