Hermione knocked smartly on Professor Lupin's office door Monday evening. The door opened a few minutes later, revealing Professor Lupin in shabby brown robes, and he arched an eyebrow at her.

"Miss Granger," he said. "What an unexpected surprise."

"I'm blackmailing you again," Hermione said promptly. "May I come in?"

Lupin's lips twitched as if he was trying not to smile, but he stepped back, allowing Hermione to join him in his office. He set about making tea, and Hermione glanced around as he did, taking a seat. The room was as barren as ever, with a Daily Prophet on his desk, the headline reading SIRIUS BLACK STILL AT LARGE. The deranged photo of Sirius Black adorned the front page once more, and for the first time, Hermione wondered where and how it had been taken.

Once the (weak) tea had been served in chipped china, niceties concluded, Lupin looked at Hermione curiously.

"So," he said. "You have more questions about werewolves?"

"I do," Hermione said, nodding. "I've helped start the process for silver wards for the hedgewitches, but that will still take some time. Months, to protect all of the tenancies." She bit her lip. "Meanwhile, though, there could still be werewolf attacks at any time. Even after they're all protected, all it would take is someone wandering outside of the wards."

Lupin flinched.

"I wish you wouldn't describe it that way," he said. "It's—it's not something anyone wants to have happen, werewolves least of all."

Hermione bit her tongue, the name Fenrir Greyback waiting to spill out.

"But it happens," she said calmly. "I need to figure out how to make sure it doesn't happen."

Lupin sighed. He leaned back in his chair, resigned.

"Then, by all means," he said, gesturing. "Ask your questions, then."

Hermione ignored his tone of voice and pulled out a list she'd penned ahead of time.

"How does the Wolfsbane potion work?" she asked first. "You have to drink it every day for the week prior to the full moon?"

"Yes," Lupin said.

"And if you forget it for even one day, it doesn't work?" she stressed. "Even one day?"

Lupin sighed.

"One missed dose renders it entirely ineffective, yes," he said. "It's not like you maintain most of your human mind. Either you take it all seven days and maintain your humanity while in wolf form, or you miss a dose and you retain none of it once you've transformed."

"And the transformation is very painful?" Hermione asked. "That's why you're so tired and miss classes the next day?"

Lupin smiled wryly.

"That, or from running around as a wolf all night," he said. "Wolves are nocturnal. They stay awake at night. You don't get much sleep when you're in wolf form."

Hermione frowned.

"How does the transformation work, anyway?" she asked. "I know it's at the full moon, but… the moon's full during the daytime too sometimes, you know? It doesn't make any sense."

Lupin shuddered.

"It's awful when that happens, the full moon rising during the day," he said lowly. "You can feel it there, prickling beneath your skin during the day… this awful sense of spiky anticipation as night draws nearer."

He paused, looking into his teacup, before looking back up at her.

"As far as I can tell, it's an astronomical magical cause," he said. "The light of the full moon has different magical effects on certain magical plants and animals. It has one on werewolves, too."

"Is it really the light of the full moon?" Hermione asked. "If it was moonlight, couldn't you stay indoors, away from all the windows, and not change?"

Lupin looked mildly annoyed.

"It's not that simple," he said. "Whatever change there is – it's as if it's in the energy of the air. It's magical. If it's nighttime, and the moon is full, you turn into a werewolf, whether you see the moon or not."

Hermione frowned.

"Define 'nighttime'," she said. "Is it when the moon rises? Or when the sun sets?"

"After dusk," Lupin said promptly. "Sunset is like a last warning to a werewolf. Once the rays of the sun are gone, the transformation begins."

"And it ends the next day at dawn?" Hermione asked, guessing. "Or at sunrise itself?"

"Dawn starts the transformation back," Lupin confirmed. "Once direct rays from the sun creep over the horizon, the night's finally over, and you change back."

Hermione made a face.

"There's no guarantee a person will always remember to take a potion every day for seven days," she said, "let alone that everyone could afford it. Even if we send all the werewolves to a forest to run and hang out together each full moon, it doesn't really solve the problem, does it?"

"Wouldn't it?" Lupin asked, lips quirked.

"What happens to the first poor sod who wanders in by accident?" she challenged. "What happens when two packs of werewolves start to fight and quarrel? What happens when the wards are weakened by accident and a mindless wolf manages to break out?"

Lupin shrugged, bleak.

"Many werewolves still keep silver chains or cages in their basements," he said. "It's agonizing, but it works."

"Yes, but it depends on them not forgetting," Hermione stressed, "or no one going down there, or them not breaking free." She scowled. "The problem is them being werewolves in the first place. If we can stop that, then the danger isn't there. But as far as I'm aware, there's no cure to that yet."

"There's not going to be a perfect solution to this, Hermione," Lupin said gently. "Short of wiping out the entire werewolf population, Wolfsbane is the best tool we have."

Hermione shot him a look, horrified.

"I'm not proposing genocide!" she protested, aghast. "Just—I don't know, if you could take an anti-moonlight pill or something, one that everyone could come to the Ministry for and take on the spot—something that stopped the transformation before it every started—"

She broke off, eyes wide.

"I—I think I have an idea," she said. "Maybe. Possibly. Probably not. It'd be expensive. But maybe."

Her mind was racing through the possibilities. She'd need to talk to someone at the Wizengamot the next day, but maybe she could…

Lupin's lips quirked.

"I find it amusing you feel so passionately about this, despite your lack of a personal werewolf connection," he told her. "Is this really from your village friends telling you horror stories?"

Hermione turned to give him a flat look.

"Because you think I'm comfortable just having a werewolf for a teacher?" she said. "One who's constantly one missed potion dose away from mauling my classmates and me?"

Lupin flinched.

"I wouldn't," he protested. "I take Wolfsbane. Professor Snape brews it for me himself, makes sure I take each dose. I curl up in my office chair with the door locked, as docile as a lamb."

"And if Snape is sick once?" Hermione said cynically. "If your last goblet is spilled, and you can't find him in time to get another one? Then what?"

Her eyes were fierce as she glared at him. Lupin looked very tired and resigned.

"It is not my fault I was bitten, Miss Granger," he chided.

"I'm not saying it is," Hermione argued. "But until there's a way to ensure that no one else can be bitten, werewolves are inherently dangerous to have around."

Lupin sighed.

"If you do find a solution, Miss Granger," he said, "you will be hailed as a hero the world 'round."