The library was unusually quiet for a Tuesday afternoon. Sunlight slanted through the tall windows, casting golden stripes across the wooden tables. Dust motes danced in the still air, and the faint scent of old parchment curled around us like a familiar spell.
Severus and I had taken over our usual corner — a tucked-away table near the Potions section, hidden behind a leaning shelf of outdated alchemical texts. The others had gone off on errands — Emmeline to deliver something for Professor Sprout, Pandora , Andrew and Felix to help Madam Pince organize charms scrolls. That left just me and Severus, hunched over rolls of parchment, quills scratching in sync.
"So," I said, eyeing my half-finished essay. "We've covered the effects of powdered bicorn horn and the stabilizing role of salamander blood. What about how mood affects the outcome?"
Severus glanced up from his notes, one brow raised. "You mean the caster's emotional state?"
"Exactly. I found a footnote in Arturo's Additives that says ingredients like asphodel are particularly responsive to intent. If the brewer is agitated, it can turn the entire potion unstable."
He nodded, intrigued. "That might explain the variability in calming drafts when used in patients with volatile tempers. I wonder if that's why Professor Slughorn said my draught worked better than the standard."
I smiled. "Probably because you brew with the emotional range of a glacier."
"Thank you," he said dryly.
We sat in comfortable silence for a moment, the only sounds being the soft flick of pages and distant footsteps echoing through the aisles.
Then I set my quill down and leaned forward slightly. "Hey, Sev… can I ask you something strange?"
"You usually do."
I shot him a look. "I've been thinking. What if there was a potion that could… I don't know… help someone stay themselves during a transformation?"
He looked up sharply. "Transformation how?"
"I mean—like… lycanthropy."
Severus blinked. "You're talking about werewolves."
"Yeah. I know it's not something we study yet, but I read about it in Dark Afflictions and Magical Ailments. Most potions only treat the aftermath. But… what if there was a way to help during the actual change? Something that could let them keep their mind, their humanity."
He stared at me, thoughtful, tapping his quill against the edge of the table. "Nothing like that exists. Most scholars think it's impossible. The transformation overwhelms the nervous system. The body goes feral."
"But what if the potion didn't fight the transformation itself?" I leaned forward, excited now. "What if it supported the mind? Anchored the person while their body changed? Sort of like… like Occlumency, but brewed."
Severus was very still, his dark eyes narrowed in concentration. "A potion that stabilizes the psyche while allowing the body to shift… That would require ingredients to both calm and fortify. And the timing would have to be precise. Full moon cycles…"
His voice trailed off. I could practically see the cogs in his head turning.
"Imagine what it could mean," I whispered. "No more chaining people up. No more hiding. Just… a life with a little more choice."
He stared at the parchment in front of him, then slowly scribbled something in the corner.
"You really think something like that could work?" he asked, almost quietly.
"I think someone as brilliant as you could figure it out."
A faint blush touched his cheek. He didn't look up, but his lips twitched.
"I'll need to research magical stabilizers," he murmured. "Possibly incorporate silver-resistant sedatives. Something like essence of moonseed, maybe…"
I grinned. "Knew you'd be interested."
He finally looked up, and there was something different in his expression. Not just curiosity, but… hope.
"Let's make it a side project," he said. "Off the books. Just us."
I nodded. "Deal."
The first night we truly began our research the candle between them flickered, casting long shadows over stacks of leather-bound books and scraps of parchment littered with notes. The library had long since emptied, the portraits snoozing in their frames and the enchanted lamps dimmed for the night. But Petunia and Severus sat close in a quiet corner beneath the high arched windows.
"This," Severus muttered, tapping a charcoal-stained finger against her notes, "is the best theory we've landed on yet."
Petunia pretended to be deep in thought, although she already knew what he would say next.
"If we anchor the aconite with powdered horned slug—here—" he underlined a section with the edge of his quill, "—we can suppress the toxic instability long enough to integrate the memory stabilizer. That's where the Jobberknoll dust comes in."
"I still think we should bind it in poppy tincture," Petunia offered. "It'll mellow the transition from one magical state to another. Prevent the shock to the nervous system."
Severus looked at her, wide-eyed with something like admiration. "You're brilliant."
She flushed but kept her tone measured. "Just well-read."
He laughed softly, more genuine than she'd heard in days. "There's well-read, and then there's you." He leaned forward, flipping through his leather-bound journal — their shared experimental log. Every page now pulsed with scribbles, diagrams, and calculations. "This isn't just theory anymore, Petunia. This could work."
Petunia watched him carefully, folding her hands in her lap. "Do you really think it could help them?"
"The werewolves?" Severus looked up. "Yes. If we get it right. If it's brewed properly, and taken over seven days before the full moon—"
"—they'll keep their minds," Petunia finished softly.
"Exactly."
They sat in silence for a moment, the weight of it settling between them. She could feel the pulse of the future in her veins — of what this potion would one day become. Of how it would save lives. And here was Severus, drawing ever closer to its creation with every moment… led by her invisible hand.
She reached into her satchel and pulled out a small sketch of a lunar cycle, annotated with potion reactions and ingredient shifts.
"You're still tracking the lunar pull on Day Three?" she asked, pushing it toward him.
"Yes. That's when the aconite becomes most volatile. The moon's magical field starts interacting with transformation magic before the physical change even begins. We need the potion to calm that storm in the mind."
She nodded. "So it needs to be started seven days before, and taken daily until the transformation?"
"Exactly." He turned another page in the logbook. "Aconite, valerian root, black lace bark, hellebore… the base is solid. But it all hinges on timing. One misstep—"
"—and the whole thing turns lethal," she finished again.
He looked at her sideways, eyebrows raised. "You keep doing that."
"Doing what?"
"Finishing my sentences."
Petunia smiled. "Well, we have spent seven days locked in this corner. I'm beginning to think we share one brain."
"We need the ingredients… and some of them are rare." I said
I exhaled, staring down at the list in front of me. Even just writing them made it feel more impossible — powdered silverweed, preserved Jobberknoll feather, tincture of monkshood... None of it was standard fare in the Hogwarts Potions supply cupboard.
Across the table, Severus leaned back in his chair, arms crossed, considering. The low firelight from the Ravenclaw common room fireplace flickered across his face.
"Don't worry," he said finally. "I'll write to Grandfather. If Mum doesn't have them in the home stock, he will."
I looked up, surprised. "Your grandfather?"
Severus nodded. "Yeah. He runs the international side of the business now — sourcing and contracts. If anyone can get rare ingredients discreetly, it's him. He still owes me a favor for fixing that shipment of spoiled Re'em blood last summer." He smirked. "It was a disaster."
I smiled, relief blooming in my chest. "That would be brilliant, Sev."
He gave a short nod, already scribbling notes on a clean bit of parchment. I turned back to the calculations I'd been working on adjusting the aconite content, when his voice cut through the quiet.
"The testing." His tone was lower, thoughtful. "We can't just brew this and guess. We need a werewolf to test it on."
My quill paused mid-stroke. My throat went dry.
I didn't say anything at first. I couldn't. Because immediately, a name came to my mind — Remus.
But it's not my story to tell. I can't that secret is his.
Severus was watching me now, waiting.
I cleared my throat, trying to stay even. "Right. Testing. That's… a big hurdle."
He frowned a little, tapping his fingers on the tabletop. "Even if we make it perfectly — if we don't know how it interacts with the actual condition, we can't be sure it's safe."
Then the thought struck me quick and sharp.
"Why not tell your grandfather about what we've discovered?"
His eyes flicked to mine, uncertain. "You think I should tell him the potion is for lycanthropy?"
"Yes," I said, sitting forward, voice gaining strength with every word. "Your family runs a potions business. They have connections, resources — they could find people with lycanthropy, maybe ones already working with Healers. They could arrange testing under the right conditions."
He was quiet.
"And if it works…" I pressed on, heartbeat quickening, "They could distribute it. Sell it. Imagine wouldn't just be some private little thing. It could help people. Real people, all over the world."
Severus was still watching me, unreadable now. He wasn't nodding — but he wasn't dismissing me either.
"You could change lives, Sev."
He exhaled through his nose, glancing away toward the fire. "But it's not fair. You're the one who started this. You're the one who thought of it."
I shook my head instantly. "No. I suggested it. That's not the same as making it real."
"You've done more than suggest." His voice was firm. "You found the right ingredients. You tracked down the alchemical pairings. "
"I didn't do it to take credit," I said. "I just… I wanted to help people. That's all."
He was silent for a long moment, then gave me a small smile .
"You're too good, you know that?"
"I've been told," I said, smirking.
"I'll write to Grandfather," he said. "I'll send the notes, the research… everything. If he thinks it's viable, he'll find a way. Quietly. And if it does work —"
He then looked me in the eye.
"I'll ask him to give you a share. A dividend."
"What?" I blinked. "No, Severus — that's not necessary."
"It is," he said. "It's only right."
I was about to protest again, but his tone stopped me. He meant it. It wasn't a courtesy. It was a promise.
"…Only if I can use it to build a private potion library someday," I murmured, half-joking.
He laughed under his breath. "Petunia Evans, Headmistress of Her Own Potions Tower."
I grinned. "Sounds decent, doesn't it?"
Then, without another word, he pulled out fresh parchment, dipped his quill, and began to write the letter.