Two days later, the Slughorn house was quiet.
Cela had just finished washing the last of the breakfast dishes when the sound of knuckles rapping on wood echoed from the front door. She paused, frowning slightly. They rarely had unannounced visitors, and when they did, it was usually a neighbor delivering eggs or her grandfather returning with some obscure herb from the market. Wiping her hands on a towel, she crossed the short hall, twisted the old brass knob, and pulled the door open.
Hermione Granger stood there.
"Hello," Hermione said, smiling a little, as if uncertain whether she was intruding.
"Ah—Hermione," Cela said, the surprise on her face melting quickly into warmth. "You came."
"I… I hope I'm not bothering you," Hermione said. "I was just in the area—well, not exactly in the area, but I asked my parents to drop me off."
Cela chuckled softly. "Bothering? No. Come in." She stepped aside, motioning Hermione over the threshold. "Grandpa's out to visit some old students of his. But… I think you might like what I've been working on."
The air inside the Slughorn House was faintly perfumed with dried lavender and something sharper—an herbal tang that seemed to seep from the very walls. Cela shut the door behind her guest, her mind already working through how to explain what lay beneath their feet. Without another word, she guided Hermione through the modest sitting room, past the dining area, to a narrow wooden door in the corner. It looked like nothing more than a pantry entrance, but when Cela opened it, the smell intensified.
A narrow set of stone steps spiraled down into shadow.
Hermione hesitated on the threshold, eyes bright with curiosity. "What's down there?"
"My workshop," Cela said with a grin, plucking a brass oil lamp from the wall and lighting it with a quick flick of her wand. "Come on, I'm not one of those big bad witches living in the jungle, kidnapping children!" She laughed, her tone teasing.
Hermione smiled, then her brow furrowed. "Wait, can you use magic outside of school when you're still underage? You live in a Muggle town, so wouldn't the Ministry of Magic detect illegal magic use?"
Cela waved off her concern with a grin. "Don't worry! You can use magic here freely. Grandpa has an alchemical artifact that keeps this house hidden from Muggles and the Ministry's detection. Even if they did notice, they wouldn't care much because of Grandpa's reputation. A ton of his former students work at the Ministry, and they respect him a lot." She paused, eyeing Hermione. "Did you bring your wand?"
Hermione shook her head. "No, I didn't."
"Good," Cela said. "If you had and used it, you might've gotten a warning letter. Grandpa says wands are linked to the Trace, which activates when you use magic in a place like this. The Ministry would assume you're breaking the law."
Hermione sighed, frustrated. "That's so unfair. I've heard pure-blood wizards or those living in wizarding villages can use magic freely."
Cela nodded. "It might seem unfair, but there's a good reason. In the past, underage students used magic illegally, and Muggles saw it—happened a lot, actually. So, they created the Trace and the law for two reasons: to stop students from doing magic in front of Muggles and to help the Ministry track where Muggles might've witnessed magic so they can wipe their memories."
Hermione frowned, processing. "But what about adults? After seventeen, the Trace is gone, right? If they use magic around Muggles, there's no punishment unless they're caught?"
"Exactly," Cela replied. "If adults get caught using magic on Muggles or breaking other laws, they could be sent to Azkaban, depending on the crime. But you can't send kids to Azkaban, so for those under seventeen, the worst punishment is expulsion from Hogwarts."
Hermione nodded, her expression thoughtful as she absorbed the explanation.
The air grew cooler with each step. The hum of the upstairs world faded, replaced by the muted drip of water somewhere in the stone. When they reached the bottom, the space opened into a wide, low-ceilinged area . It looked like something from another century—rows of wooden shelves bowed slightly under the weight of jars filled with ingredients: bundles of dried herbs tied with twine, stoppered bottles of shimmering liquids, boxes of crushed minerals. A long workbench dominated the center, already laden with a copper cauldron, scales, knives, and a mortar and pestle.
Hermione's mouth fell open just slightly. "Merlin's beard…"
Cela smiled faintly at her reaction. "This is where I spend most of my time."
"It's incredible," Hermione breathed, stepping forward to look at a row of neatly labeled phials. Her eyes darted over the script: Essence of Belladonna, Dried Knotgrass, Salamander Blood, powdered Moonstone. "You made all of these?"
"Most of them," Cela said, setting the lamp down on the bench. "Some came from my grandfather's own stores, but… I like to keep busy."
Hermione turned back toward her, her expression a mixture of awe and something like admiration. "You're brilliant."
Cela laughed quietly. "Thank you, but I think you might be exaggerating."
"I'm not," Hermione said firmly. "Last year, I brewed a Polyjuice Potion in my second year at Hogwarts, and I know how difficult that is. Looking around here… well, it's like you're running your own advanced N.E.W.T.-level potions lab."
Cela's eyebrows rose. "Polyjuice Potion? In your second year?" She leaned slightly against the workbench, arms folded. "That's impressive, Hermione. Most adult wizards and witches wouldn't even attempt it without a potion master's oversight."
Hermione flushed slightly under the praise. "It… didn't exactly go perfectly," she admitted. "We made it in the girls' bathroom—well, a bathroom called Moaning Myrtle's bathroom—because it was the only place we could work without being interrupted. But the ingredients… Merlin, some of them were nearly impossible to get. Boomslang skin, lacewing flies stewed for twenty-one days…"
Cela listened intently, her expression sharpening with interest. "And what was the purpose of brewing it?"
Hermione hesitated for a moment, then said, "We needed to get information from someone… someone who wouldn't exactly have been willing to talk to us. We disguised ourselves as other students."
Cela's lips curled into an amused smile. "That sounds very Gryffindor to me. Don't tell me I guessed right—you're a Gryffindor, aren't you?"
"Well, yes, I'm a Gryffindor," Hermione said, rolling her eyes. "And it's terrifying to think about getting caught. If Professor Snape had seen us—he's the Potions Master—he'd have pushed for expulsion."
Cela tilted her head thoughtfully. "Snape… my grandfather used to mention him. He taught Snape and a woman named Lily Evans. Grandpa said they were the smartest and most talented Potions students he had in his final years teaching at Hogwarts."
Hermione's eyes widened. "He did? That explains so much." She glanced around again, her curiosity pushing her to step closer to the shelves. "So… what are you working on now?"
Cela moved to the cauldron, where water simmered quietly over a low blue flame. "Something simple. A mild restorative draught—useful for clearing fatigue. Want to help?"
Hermione's expression brightened instantly. "Of course."
Cela handed her a small bundle of herbs. "Peppermint leaf, for clarity of mind. Start by stripping the stems and adding the leaves to the mortar."
They fell into an easy rhythm—Cela measuring powdered root into a small bowl, Hermione grinding leaves with practiced motions. The air grew fragrant as they worked, mint mingling with the earthy scent of ground valerian. As they brewed, the conversation naturally drifted.
Hermione talked about Hogwarts in vivid detail—the Great Hall with its floating candles, the shifting staircases that sometimes seemed to have minds of their own, the way snow fell through the enchanted ceiling in winter. She described Professor McGonagall's stern fairness, Professor Flitwick's boundless enthusiasm for Charms, and Hagrid's oversized but endlessly kind presence.
Cela mostly listened, occasionally asking quiet questions. "What's the library like?" she asked at one point, her tone betraying genuine interest.
Hermione's face lit up. "Enormous. It's like… like stepping into another world. Rows upon rows of shelves, ancient tomes, spellbooks… Madam Pince, the librarian, can be a bit strict, but if you're careful—oh, Cela, you would love it there."
Cela smiled faintly, stirring the potion as Hermione spoke. "Maybe someday I'll see it."
"You should," Hermione said earnestly. "You'd fit right in. You've got the mind for it."
They moved through the brewing process with companionable ease—adding crushed rosehips for circulation, stirring counterclockwise three times, letting the mixture simmer until it turned a soft green. Every so often, Hermione would drift into another story—a near disaster in Potions class when Seamus Finnigan's cauldron had exploded, the time Peeves the Poltergeist had locked all the first-years in the broom cupboard, the chaos of the Halloween nights.
Cela listened, storing away each detail like a treasure. Hogwarts sounded nothing like her quiet, sheltered days at home—but hearing Hermione speak, it felt almost as if she'd walked those corridors herself.