Taming the True Fire (HP)

It seemed Catherine's plan had worked. The very next day, she spotted Snape and Lily together after lunch, as close as ever. The red-headed girl was even holding his hand, speaking to him with a serious, sincere expression.

However, the young witch had little time to focus on Snape's troubles since she was completely consumed by the final preparations for brewing the Animagi Potion. By Friday evening, she, James, and Sirius slipped into the Room of Requirement, hidden beneath James' Invisibility Cloak.

"It's getting a bit tricky for all three of us to fit under this thing." – James muttered, frowning as he was folding the cloak.

"I didn't ask to come." – Sirius grumbled, earning an annoyed look from James – "I still don't see how I'm supposed to help."

"Better you than Peter." – Catherine quipped, setting the first batch of ingredients on the counter – "At this point, just staying out of my way is plenty."

"I can never tell if you're complimenting or insulting me." – Sirius smirked, pulling a small package from his robes - "Where do you want the griffin claws?"

"I don't know. Just put them somewhere I can find them later." – the girl replied, focused on finely cutting Valerian roots with a silver knife – "It's one of the last ingredients we'll need—about two months from now."

Sirius shrugged half-heartedly and scanned the lower shelves above the hearth for an empty spot. His mood had been rotten for days, and Remus' casual indifference only fuelled the simmering anger he was struggling to keep in check. If he was honest with himself, he wasn't sure who he was angrier at—Remus, Catherine, or himself for not being the first one to kiss her.

He didn't want the young witch to know about any of it, but a small, petty part of him wished she did—wished she felt embarrassed, or even better, regretful. The memory of her disapproving glance after Marianne kissed him sparked a brief, bitter satisfaction. For a moment, he almost savoured it.

'Did I really hope she'd be jealous?' – he wondered with a sharp twinge of self-reproach, shoving aside a few old boxes to make space.

"I'm putting the griffin claws next to the chest with the Ashwinder egg." – the boy muttered, eyeing the heavy chest made of Goblin silver - "Where did you say you got this again? Goblin silver's not exactly easy to come by, never mind the price."

"I bought it at an antique shop." – Catherine replied, focused intently on grinding moonstones with a grim, almost mechanical precision.

"You don't say…" – Sirius murmured, his voice low and mocking.

"What's your problem?" – James asked, appearing at Sirius' side – "One would think we forced you to come here."

Sirius scoffed. "Well, at this point, it's starting to feel a little forced, yeah. And since you and Catherine are keeping so many secrets between yourselves these days, mind explaining why she keeps lying to me about this chest?"

"What chest?" – James asked, confusion flickering in his eyes before his expression turned angry – "For Merlin's sake, would you knock it off? We're not hiding anything!"

"Maybe not you, mate." - Sirius replied, his tone growing darker - "But she is. That engraving on the chest lid—it's the McMahon coat of arms."

"What?" – James turned, glancing toward Catherine, who was busy dividing Moonlit dew into containers, preparing some to be frozen and others to be boiled – "Are you sure?"

"Of course I'm sure." – Sirius growled – "That prat Greg McMahon had the same bloody thing embroidered on his cloak last time we were in Hogsmeade. It's impossible to miss."

"You think McMahon gave her the chest?" – James asked, his voice quieter.

"Almost certainly." – Sirius spat – "I wouldn't have liked it if she'd gone to him, but I could've understood—these things are rare. But it's the lying that gets me. It feels like she's mocking me, going out of her way to make a fool of me."

"This isn't true and you know it." – James snapped, his frustration breaking through – "If McMahon really gave her the chest, maybe she didn't tell you because you always overreact."

"Rich coming from you." – Sirius scoffed – "Weren't you the one pulling branches from his broom while he was showering after practice this week?"

"That's different!" – James hissed, a flicker of embarrassment colouring his face – "Besides, in hindsight, I regret my actions."

"Sure you do!" – Sirius replied with a sarcastic laugh – "Oh, by the way, Snivellus and Evans are looking cozy again. Thought you'd want to know."

"One problem at a time!" – the other boy groaned with irritation.

"Are you two going to help, or just gossip like a pair of old hags in a Provençal village?" – Catherine's sharp voice cut through, causing both boys to snap their heads in her direction.

"I thought you didn't want people in your way." – Sirius smirked, grabbing the heavy cauldron from her hands and hoisting it above the hearth.

"Only people who don't know what they're doing." - she retorted with a smile, pointing her wand at the firewood - "Incendio!"

Flames sprang up under the cauldron, and soon the liquid inside was bubbling violently. Catherine quickly added the Murtlap essence, stirring the mixture as it turned a deep violet.

"I can't believe we've finally started brewing that bloody potion!" – she exclaimed, excitement flashing in her eyes – "Next week, I'll add the Moonlit dew and start preparing the Ashwinder egg. It needs to be stored at the right temperature for a whole month!"

"I just hope you won't poison us with that thing at the end." – Sirius teased, though his gaze flickered toward the silver chest with McMahon's coat of arms engraved on it.

"If you think you could do better, be my guest!" – Catherine shot back, her tone suddenly harsh. She turned on her heel and stormed toward the door.

"Great job!" - James muttered under his breath, glaring at Sirius before chasing after her – "Flame, wait! It's after curfew! You don't want to run into Thorne—you'll end up in detention till Easter!"

"Don't worry." - Sirius said with a bitter smile as he watched them go - "She won't quit. Not when this is all for Moony."