After their visit to Hagrid, Ginny caught up with the others back in the common room. They discussed what to do about Buckbeak, but couldn't come up with anything besides Hermione's usual strategy of researching the problem in the library.

Harry struggled to focus. He hadn't been able to bring himself to confront Hagrid after seeing the state the man was in, but he'd realized Lupin had probably also known Black quite well. He couldn't let things rest until he confronted Lupin about what he knew, and Ginny insisted on accompanying him.

When Lupin answered his office door, he looked surprised to see them outside a scheduled lesson, but invited them in. As Harry started to relate what he'd learned, Lupin's face closed off, and he deflected Harry's questions as usual.

Okay, Ginny thought, I was way off about Hagrid, but this time something's going on for sure.

She remarked, "It must be awful to think about someone you knew turning out so bad."

Lupin turned and met her eyes. She figured a Defense teacher would have more cause to practice Occlumency than a groundskeeper, so she brushed against his mind even more lightly than she had done with Hagrid.

At which point she got her second shock of the day, as what she found in his mind was a raging beast.

Ginny's wand was out and pointed at him before she realized she was reaching for it.

Lupin frowned at her. "Is there a problem?"

"Ginny?" Harry asked in confusion.

"Harry, we have to go," she said.

"Perhaps that would be for the best," Lupin said.

"Why, what's going on?" Harry asked. "He hasn't answered anything we came to ask."

"Harry, please trust me," Ginny urged.

"Fine," Harry said and headed for the door. Ginny kept her wand pointed at Lupin until they were out of the office with the door shut behind them, and on their way down the corridor.

"What was that about?" Harry asked.

"He's dangerous."

"Not this again. Why did you agree to come if you were going to pull me away before I got any answers?"

"No, I'm sure of it now."

"Why? What happened?"

Ginny pulled Harry into an empty classroom, and shut the door behind them.

"I haven't told you everything about what happened with Riddle," she began.

"Okay. You know you can tell me anything. Whatever he did to you, or made you do, none of it was your fault."

"This isn't about what he did. It's about what I willingly agreed to."

Harry shook his head, but she said, "No, listen. I told you how before he took over, he acted like he wanted to be my friend, and seemed happy just sharing cool stuff about magic with me."

"Yeah. That part didn't sound so bad."

"It wasn't, at the time. Before I know who he became."

Harry shrugged. "Yeah, now you know. At the time, you didn't."

"I let him in my mind."

"He forced his way in. You had no choice."

"No. Not at first."

He frowned. "I don't understand."

"There's a type of magic called Legilimency which is sort of like mind-reading. It's more complicated, but that's the basic idea."

"He did that to you?"

"Yes. And I let him. And he taught me to do it to other people."

Harry considered this, then turned red and looked away. "Uh, listen. If you've seen anything in my mind that, you know, made you uncomfortable or whatever, I swear I didn't mean anything by it."

"What? No, I've never used it on you. Riddle is the one you need to worry about. He could do it when he was at Hogwarts, and the rumor is he got even better later. A lot better."

Harry's eyes went wide. He threw his hands up in frustration. "Well, of course. It's not bad enough for him to know a hundred times more spells than me. Of course he also has to be able to see any plan I might come up with."

"There's a way to protect your thoughts. It's called Occlumency. I've been meaning to talk to you about this for a while."

"What stopped you?"

She looked down. "I was too ashamed. It makes me sick to think of sharing something so…" She paused, as her lip curled in disgust. "Something so intimate with someone who turned out to be such a monster. And I let him in. I let him do it."

Harry stepped forward and wrapped his arms around her. "I'm sorry you had to go through that."

She clung to him in silence until she was sure she wasn't going to burst into tears from sheer relief.

She pulled back to study his face. "You're not angry? Or suspicious?"

"No. Why would I be?"

"I don't know, maybe because I had your worst enemy messing around in my head and training me to do his bidding. Or because I was so damn eager to learn everything I could from him?"

"I already knew most of it. You told me about him teaching you, and later making you see things. I just hadn't put it together that he would need some way to know what images to show you."

"Do you see me differently now?"

"Of course not. Well, except for being even more amazed at how strong you are to have made it through it all."

She let him pull her back against him. She wasn't sure she believed him, as she was sure he would comfort her and tell her everything was alright, even if it wasn't. And if he truly didn't blame her, it just meant he hadn't thought about it enough yet.

Even so, she was happy to accept this reaction. Telling him could have gone a lot worse. At least he didn't run, or pull his wand on her.

"We should head back," she told him. "We have to tell the others."

"Tell them what?"

"About Lupin," she said, casting an uneasy glance back towards his office. She took Harry's arm to get him moving in the other direction.

They found Hermione and Ron in the common room, and led them out into the corridor to talk.

Ginny started by telling Ron, "Okay, the short version of the story is that I know Legilimency. Magical mind-reading."

Ron said, "You better not be using it to cheat at chess."

Hermione turned to him. "That's your biggest concern when you find out this sort of magic exists?"

He shrugged. "Magic lets you do loads of weird things."

Hermione scowled, but Ginny said, "Before the two of you get started, please don't. I learned something you all need to know."

As she began to describe the encounter with Lupin, Hermione was appalled to hear she had used Legilimency on anyone, let alone a teacher. Ginny brushed this aside, pushing on to explain what she'd found.

Hermione reflected for a moment, then said, "Oh, don't worry. You must have seen the wolf in him."

"What wolf?" Ginny asked.

"Professor Lupin is a werewolf. None of you knew?"

Ron burst out, "A what? A w–"

Hermione pressed her hand over his mouth. "Shhh! You know what sort of prejudice there is towards people with that condition."

"Condition?" Ginny hissed, struggling not to raise her voice as Ron had. "It's a curse, and an incredibly dangerous and transmissible one."

"It's only dangerous or transmissible during the full moon. I'm sure Professor Lupin and the headmaster have arranged suitable precautions."

"Like the precautions to protect the Philosopher's Stone?" Ginny shot back.

Ron pushed Hermione's hand away. "Dumbledore hired a werewolf? Is he mad?"

Hermione frowned. "I didn't expect this sort of bigotry from either of you."

"Bigotry?" he asked in disbelief. "This isn't some nonsense like blood purity. This is turn into a wild beast and eat your face off reality!"

"Shhh! He's been here almost four months now, without incident. Dumbledore obviously has safeguards in place. I'm more concerned about your reaction."

"Werewolves have a raw deal, no doubt about it. That doesn't make them any less dangerous."

Ginny added, "You may be willing to accept the risk, but what gives you the right to decide for everyone?"

Hermione said, "I'm not deciding for everyone. I'm sure other people must have figured it out. The evidence is all there; the way he's always out sick on the full moon, the form a Boggart shows him, Professor Snape's essay assignment… I can't be the only one in the entire school capable of basic reasoning, so all those people must be fine with it too."

"What are you talking about? What about Boggarts and Snape?"

"Boggarts take the form of a full moon for him. You haven't noticed in your extra lessons?"

"He always lets Harry face it. When he has to step in, he banishes it before the Boggart has time to shift. And what essay?"

"The essay Professor Snape assigned at the end of his lesson on werewolves, of course."

"Snape didn't mention werewolves in my class."

"Oh. Maybe that was just in our class." Hermione frowned. "Maybe he intended it as a message for Harry, because Professor Lupin had taken an interest in mentoring him."

"Or maybe he intended it as a message for you, because he thought you'd be capable enough of basic reasoning to figure things out and warn people."

"This school is full of people who would make things needlessly difficult for Professor Lupin if they knew. I'm disappointed to find two of my friends may be among them. Please don't go spreading this around."

"I'm telling my brothers. I haven't decided yet about the rest of the school."

"At least talk to Professor Lupin before you do anything you can't take back."

Harry put in, "We just tried to talk to him about Black, which went nowhere, just like always. How many chances are we supposed to give him?"

Hermione turned to him. "Not you too."

"He refuses to explain anything. Ginny's right about it looking suspicious, werewolf or not."

"Fine. What do you think about him being a werewolf then?" she pressed. "Are you prepared to see him ostracized for something he can't help?"

Before Harry could answer, Ginny said, "That's not fair. If he ran a shop in Diagon Alley or something, I'd be happy to shop there, though I'd be damn sure to double-check the time of day and phase of the moon before going in. But as things stand, we're spending full moon nights in the same castle as a werewolf Defense teacher who keeps loads of secrets, including ones about the escaped killer who's after Harry."

"Harry? Does she speak for you?" Hermione pressed.

Harry said, "I don't know. Everything Ginny listed off sounds bad, but after getting to know him, even the little he's let us, he doesn't seem evil."

Ginny said, "The worst ones never do, on the surface. I've learned the hard way you can't judge a book by its cover."

Harry gave her a sympathetic look, but said, "Until now, you've been willing to accept the rest of it–the Defense curse and all his secrets. I don't see how this changes much. He's only dangerous during the full moon, and he hides away somewhere during those times."

"Exactly!" Hermione agreed. "In fact," she added to Ginny as the thought struck her, "this should take care of your worries over the Defense curse. This explains why he won't last more than a year–baseless prejudice. It's ugly, but at least we know what the issue is now. And it's quite manageable."

Ron and Ginny exchanged a look. Ron said, "They don't get it, because they didn't grow up with it."

"Thank goodness," Hermione said.

Ginny said, "Yes, it's only a problem during the full moon, but then it's a big problem. I've seen the beast inside him for myself. That's not something any of us ever want to face when it comes out."

Ron asked Hermione, "What happens if he does get loose while he's changed? I suppose you think you're going to stroll up and cast a spell to turn him back, like Lockhart claimed he did once."

"I'm not saying it will be easy, but I know the spell," she answered. "I'm not ignoring the possible dangers."

Ron shook his head.

Ginny said, "Nobody wants to lose him as a teacher. Harry and I are both learning a lot. But werewolf curse plus Defense teacher curse equals a wand pointed at someone's head. Not to mention whatever history there is between Lupin and Black and Harry's parents, which he won't tell us about."

Hermione said, "It could be as simple as him finding the past too painful to discuss, with the friends he's lost, and the difficulties he must have faced because of his condition. We have to give him one last chance to explain. We'll lay out all our concerns, so he understands we aren't asking out of idle curiosity."

They all agreed, with varying degrees of reluctance.

Before leaving to confront Lupin, Ginny insisted they tell Fred and George, so someone would know where they'd gone. Hermione considered this precaution unnecessary, reminding her it wasn't a full moon. Ginny responded by reminding Hermione of the existence of memory charms.

Fred and George weren't happy with the plan, but agreed to wait behind for their return.

~*~

They arrived outside the Defense classroom, and Harry knocked.

Lupin opened the door. He took in the group, glanced down the corridor, then looked back at them.

"I thought I might have more visitors this evening," he said, before stepping aside to allow them to enter. "Though I was expecting you to bring more reinforcements, including at least one teacher. Ah, well. You're here now. Tea, anyone?"

"We didn't come for tea, and other people know we're here," said Ginny.

"Ah. Excellent. I'm pleased to see my time teaching you Defense hasn't been all for naught. I assume you have questions…"

Harry asked, "How well did you know my parents and Sirius Black?"

Lupin blinked. "Is that truly what you most want to ask about?"

"No," Ginny said, but Hermione shushed her.

"Are you going to try to bite us?" Ron demanded.

"Ron!" Hermione said.

"Mr Weasley," Lupin said in a mild tone, "even in the old days, when Hogwarts permitted corporal punishment, I don't believe biting was ever employed in the discipline of students."

Ron stared at him. "What? We know you're a werewolf."

"Indeed. Perhaps I should have allowed Professor Snape's essay assignment to stand. You might have learned that a werewolf's bite is only infectious during a full moon. Even if I wished to spread this terrible curse–which I assure you I do not–we are not in that phase of the lunar cycle. I'm afraid I can see no possible motivation for such an uncivilized action on my part."

"Did my dad know about you?" Harry asked.

"He did."

"And he was okay with it?"

"James Potter was one of the best friends I've ever had, or ever expect to have. He put in an extraordinary amount of effort to help make my condition more bearable."

"Then I'm okay with it too."

Lupin smiled. "You have so much of both your parents in you."

"Harry," Ginny warned. "Your dad was his friend a long time ago. People change."

"Also, you have only my word for it," Lupin added helpfully. "Your wisest course of action would be to confirm everything I tell you with the headmaster."

Harry studied Lupin's face. "I believe him," he decided. "I have pictures of a guy with my dad that could be him, though he looks…" Harry trailed off.

"Much older now? Yes, well, the curse does take its toll."

Ginny insisted, "There's still the Defense teacher curse."

Hermione said, "I've been thinking it over some more, and I think I have a solution."

Lupin turned to her. "Oh?"

"You could hand in your resignation to Dumbledore tomorrow, dated to take effect at the end of the school year."

"If the curse is real, I'm not sure I can evade it through a mere technicality."

Hermione said, "If everything is already decided, and making good choices doesn't matter, what's the point of doing anything? Why would you come here, if there's even a chance the curse is real, and there's nothing you can do to avoid it?"

"Perhaps there are times when doing what you know to be right must be an end in itself."

"No. Making good choices has to matter. Won't you at least try, Professor?"

"Very well. I will do so tomorrow, if for no other reason than to set your mind at ease that you've done everything within your power to help."

"Thank you."

"Of course. And thank you for your concern."

He turned back to Harry. "As for everything else you've asked me which I've declined to answer… Given the tone of our earlier meeting, I thought my time as your teacher might be coming to an end soon. This led me to reflect on what I wanted to say to you while I still have the chance. It's long past time I told you everything I can."

Harry said nothing, and waited for him to speak.

Lupin took a breath, then began, "I had three close friends as a student here, and in the years following. Your father was one of them. Sirius Black was another. The four of us shared a bond which made it unthinkable that any could ever turn against the others. Or so I believed, up until the night Black betrayed your parents to Voldemort, then went on to murder the fourth member of our group, Peter Pettigrew, along with a street full of Muggles."

Harry swallowed. "But why? Why would Black turn against everyone?"

"I've been pondering that question for more than a decade now, without success. Looking back, there were signs he was dangerous as early as our school days. He had a tendency to go too far in our rivalry with the Slytherins. Or he may simply have gone mad. He appeared so at the time of his capture, and with the family he came from… Well. This is all speculation."

Ginny said, "There's a big difference between going too far with enemies and betraying your friends."

"It certainly feels that way when you're on the receiving end. I spent years obsessing over how everything could have gone so wrong, trying to make sense of it. Eventually, I accepted I wasn't going to find any answers, and had to move on and put it behind me. Wallowing in negative emotions is bad for anyone of course, but for those of us gifted with magic, doing so can lead one down a very dark path indeed."

Lupin turned to Harry. "Part of why I've been reluctant to discuss this is that I don't have any satisfying answers to give you. If you find any, please let me know. Though I implore you not to go looking, for your safety and well-being, both physical and mental."

Harry said, "It's not that simple. Even when I don't go looking for trouble, it comes looking for me. I still wish you'd explained sooner. It would have seemed a lot less suspicious."

Lupin sighed. "Yes, I see that now. Please understand that when I made the decision to put the past behind me, it wasn't just a matter of realizing I would never make sense of it. After everything went wrong, remembering even the good times became… difficult. All my closest friends from those days are gone, in one way or another. I couldn't save them, but I promise to do everything I can to prevent the same thing from happening to your generation."

Harry and his friends gave each other troubled looks.

Hermione said, "I can't imagine losing even one of my friends like that, never mind all of them. We're sorry to make you relive it."

Harry said, "Yeah, sorry. We weren't prying just for the sake of it."

"I know," said Lupin. "I can see how suspicious my behavior must have appeared."

Ron asked, "Why is Black after Harry? That's the real question. Not how he went bad in the first place."

Lupin said, "It may relate to whatever led his master to attack the Potters. Or he may desire revenge for Harry's role in his master's downfall."

"You don't know why Riddle come after us in the first place?" Harry asked.

"No. I knew your parents planned to go into hiding, but I never learned why. There was a war going on, and the group we joined to fight Voldemort feared a spy in our midst, long before Black revealed his true allegiance. None of us shared information more than necessary. The headmaster may know more, but if so, he must have some reason for keeping it to himself all these years."

Harry gave a frustrated sigh. "I see."

"Professor," Ginny said, "You're a fantastic teacher when you're–as you are now, but…"

"But you wish to know what precautions I'm taking when I'm not as I am now."

Ginny nodded.

He said, "Around a decade ago, a potioneer named Marcus Belby developed a formula known as the Wolfsbane Potion, after its primary ingredient, Aconite. It allows a werewolf to maintain their mental faculties while transformed. Professor Snape has been good enough to brew it for me."

"A decade ago?" Hermione asked. "Why are people still afraid of werewolves, if they haven't been a threat for years?"

"The potion is difficult to brew, and its ingredients quite expensive. Given the financial state in which sufferers of the affliction often find ourselves… Well, suffice it to say, the potion has never entered into widespread usage."

Hermione stared at him, then pulled out a notepad and pen and began furiously writing.

Lupin gave her a bemused look, then turned to Ginny. "Satisfactory?" he asked.

Ginny hesitated. "Under ordinary circumstances, I know you would never neglect something so important. But with the Defense curse–"

"I already explained the solution for that," Hermione put in.

Ginny gave her a skeptical look, but moved on with her questions. "And Black? Any idea how he got into Hogwarts? Or why he's immune to Dementors?"

"Immune? Unlikely," Lupin answered. "It's possible to bargain with such creatures up to a point, but anyone with human emotions remains susceptible to their influence, no matter what Dark Arts he may have practiced. What makes you think Black is immune?"

Harry said, "The paper said he acted calm in Azkaban, despite years of exposure. I don't see how he could manage the Patronus Charm. It's hard enough with a wand, which I assume he didn't have."

"True. Even if he somehow obtained a wand, Dark wizards are as a rule unable to achieve the proper emotional state to produce a Patronus."

Ginny asked, "What about spells based on other emotional states? Something a Dark wizard could manage?"

"I don't believe any spell powerful enough to drive them away would be possible without a wand."

"Hold on," Harry said. "Are you saying there are other ways to fight off Dementors if you do have a wand? Maybe I'd have better luck with one of those."

Lupin gave him a grave look. "Intentionally generating negative emotional states begins to stray into the realm of the Dark Arts."

Ginny argued, "Not all negative emotions are Dark. Anger can be righteous."

Lupin frowned. "This is a dangerous line of inquiry. Besides the dangers inherent in the magic itself, explorations in this area are strongly discouraged by the Ministry. You are free to ask me such questions, but be cautious about raising the topic with anyone else."

"Understood. Will you answer my question?"

"I don't know whether other methods would work against Dementors. If anyone knows, they have not shared their knowledge with the magical community at large."

Harry said, "Black managed to get past the Dementors and into Hogwarts somehow."

Lupin said, "He must be using some form of Dark Arts he learned from his master–probably the same method he used to become the only prisoner to ever escape from Azkaban."

"Hmmm," Ginny said. "Then you don't think he's using the secret passages into the castle?"

"And what would you know about those?" he asked sharply.

"With all due respect, isn't it more important what Black knows about them?"

"If such passages existed, I'm sure the headmaster has closed them off, or has someone monitoring them. Even so, you should all steer clear of any you have discovered. And above all," he added, addressing Harry, "do not attempt to use them to leave the castle for any reason. Other dangers besides Sirius Black lurk outside these walls."

"I know," Harry said. "I haven't forgotten what happened at the front gates."

"As horrible as the mere presence of a Dementor is, it's not the greatest danger they pose."

"What could be worse?"

"The Dementor's Kiss–a euphemism for a fate that's an abomination even when inflicted on those who have done abominable things. The Dementor clamps its mouth over its victim's, then draws out and consumes the poor unfortunate's soul, leaving them nothing but a husk with a still-beating heart and still-breathing lungs."

Harry said, "If they get hold of Black, couldn't happen to a nicer guy."

Lupin frowned. "Don't be so hasty in your judgments. Imagine, a living person reduced to an empty vessel with no mind, no self. Everything they are–ripped away, forever. Is that truly your idea of justice?"

Harry hesitated. "I don't know. I'll have to think about it some more."

Lupin nodded. "Was there anything else?"

"I don't think so. We'll see you at our next lesson, then? If you're still willing to teach us?"

"For as long as you still wish to learn."

Harry and Lupin both turned to Ginny, who nodded. "I'll be there."

Lupin said. "Good. Although I find discussing the past difficult at times, I will try to be more open with you. In return, I hope you'll both ask me anything you wish to know–rather than attempting to use Legilimency on me."

He focused on Ginny, who asked, "Legilimency? What's that?"

"You were more subtle than some, but not so subtle as you may have intended. This is not magic to cast lightly. Aside from the ethical issues, you may not always like what you discover."

"I'm starting to get that idea," she admitted. "As far as ethical issues, I've never used it except when I see a potential threat."

"I hope you see the obvious problem. If you're always searching for threats with it, one day someone dangerous may notice you using it on them, and perceive you as a threat."

"I'll be careful."

Lupin said, "I hope so. Now then, if there's nothing else, let me take the opportunity to wish you all a Happy Christmas, as I will be indisposed during the Christmas feast."

The students wished him the same in return, and took their leave.