Chapter Text
Hermione Granger had always prided herself on solving problems, but that was until one problem got a monopoly over her mind.
Equations, essays, impossible spells-- none of it fazed her. But Siren Rosier? Siren Rosier was a problem she couldn't crack. The one riddle she didn't know the answer to.
It started with a ruined potion. A single mint leaf, perfectly placed, perfectly timed, perfectly invisible. Hermione had replayed that Potions class a dozen times in her mind, analysing every angle, every possibility. She never stopped bothering Harry and Ron about their theories. And yet, she kept coming back to the same impossible conclusion:
Siren Rosier had sabotaged her work. On purpose. For no reason.
Well. No reason Hermione could see.
Three weeks later, she still couldn't let it go.
Three weeks earlier
The dungeon smelled like freshly cut herbs and brewing potions, a faint smell of rotting ingredients coming from a closet everyone knew to avoid.
Siren stood in the back of the classroom, Draco and Pansy on each side as she stirred through their potion. "Can you believe it?" Draco huffed with an eyeroll, his mind flickering back to their previous period. "Hagrid is teaching us. I've never even seen him use magic!"
"He does know a lot about magical creatures," Pansy mused, her hip leaning against the table. She ignored the ache of the sharp edge digging into her bone as she rhythmically poured a tiny amount of bat blood into the cauldron.
A snort left Draco's lips as he crossed his arms. "I hope so; as the Care of Magical Creatures professor, that seems like the bare minimum,"
Siren tuned out her friends' conversation as she glared at the Gryffindor girl in front of her, her mind wracking on possible ways she could get a better grade than her. Ever since the last time Hermione had been smug about getting a higher grade, she vowed to make sure it would never happen again.
Her gaze flickered from the leaf of mint on the corner of her table, a smirk curling onto her lips as a plan grew in her mind. She glanced at Draco and nodded in agreement. "Did you hear, Potter called you a 'mother's child' a while ago?"
Offence flickered through his eyes as his head snapped towards the brunette boy. "Potter!" He hissed, annoyance evident in his voice.
Harry sighed and glanced at Draco, boredom written across his face. "Yes, Malfoy? What do you want?"
"Did you call me a mother's child?" Draco's voice held an accusatory tone, his arms folded across his chest.
A smirk curled onto Harry's face as he leaned against the desk. "No, but I would've had I thought of it. Why?"
"I can see why you don't think of mothers, you're lacking in that area, aren't you?" Draco sneered, and a flicker of hatred rested in his eyes.
Harry's lip twitched in anger. "I'd rather have no mother than have yours, Malfoy, or did you forget the howler you got for getting an E?"
Draco pretended not to care about Harry's statement, but by the way his hand curled around the desk, it was clear it was affecting him. "It's nice pretending you have a choice, right, Potter?"
Harry opened his mouth to retort with another jab, causing Hermione to scoff in annoyance and turn around. "Harry, just ignore him; he's not worth your time."
There you go, Siren thought to herself. Her fingers brushed the polished wood of her wand, an almost non-existent whisper falling from her lips. Wingardium Leviosa. The leaf obeyed almost instantly-- it floated towards the other table and hovered above the cauldron.
As Draco called Hermione a mudblood, the leaf dropped into Hermione's cauldron and slowly sank to the bottom. A smirk graced Siren's lips as it started to bubble and became a seafoam colour.
"Harry! You made me lose focus!" Hermione screeched as she began stirring quickly.
Harry sighed as he scratched the back of his head. "What do you mean, it's green, isn't it?" Confusion echoed in his words, as the potion was supposed to be green.
"It's seafoam coloured, Harry!" Hermione snapped as she helplessly tried saving it. Her attempts were in vain, of course, as every ingredient she used only made the seafoam colour more opaque.
"That's a shade of green!" Harry argued as he offered to drop a red berry into the cauldron.
Barely on time, Hermione managed to snatch the berry from his hand. "The wrong shade. And you just almost made it explode!"
A gleeful chuckle bubbled from Siren's chest as she watched her classmates argue about the situation she created. Her gaze dropped to her perfectly brewed potion, causing a proud smirk to curl onto her lips.
"You used me," Draco stated flatly, a mix of annoyance and amusement in his eyes. As soon as he saw Siren smirking, he knew what she had done, but he was curious about why she'd done it, so he allowed it to play out.
Siren shrugged halfheartedly as she poured a bit of the potion into a phial. "For comedic purposes, though,"
"Your only salvation," A smirk graced Draco's lips as he sat down behind the desk, watching as Siren flaunted her perfect potion when she gave it to Professor Snape. "And people call me mean,"
"They call me mean, too," Siren said as she sat down next to Draco. "Just never to my face,"
Hermione, who overheard Siren calling herself mean, rolled her eyes in annoyance as she made eye contact with Harry. "Can you imagine being proud of being mean?"
"I suppose that in their world it's like being nice for us," He shrugged, mind half occupied by other things.
A scoff left her lips as she narrowed her eyes at the perfect phial with her name neatly written on it. "With her perfect potion, and her perfect handwriting." She muttered hatefully under her breath.
"Calm down, Moine," Ron said after a moment. "You'll save the potion and get a higher grade than she will," He knew the potion was doomed, but he knew better than to actually voice his thoughts.
Hermione sighed and shook her head dramatically. "Once it becomes this colour, it is hopeless; we need to start over."
Both boys immediately began protesting, causing a snicker to leave the table behind them. "Come on, Hermione, we don't have that much time," Harry's eyes fixated on the clock, where the arms pointed at half past ten.
"He's right, we need 45 minutes for this potion, we've only got thirty." Ron agreed, his voice hopeful.
"But it's not the right colour!" Hermione snapped as she examined the book. The ideal colour filled the page next to the recipe, along with a picture of the ideal texture.
Ron smiled meekly. "If that's the only problem!" His voice was cheerful as he dug a tiny box from his bag. Inside the box were three even smaller bottles.
After a bit of meddling, he managed three dots of each on the coaster: a yellow dot, a red dot, and a blue one. With a dull knife, he began stirring some of the dots together until a colour similar to the page coated the point of the knife.
"Ronald, what is that?" Hermione asked suspiciously, hesitant to inspect the mysterious liquid closer.
Ron grinned proudly as he stirred the knife into the cauldron, causing the potion to turn grass green. "Food colouring!"
Hermione's eye twitched as she stared at the potion. While it had the right colour, Hermione didn't know what to think of it. "Ron, that's cheating."
"No, that's winning,"