Chapter 18 – Ill Met By Moonlight

Daphne's mural of Umbridge as a fun-sucking vampire was a hot topic over the weekend, although Harry knew that by the time lessons came back around the next week, people would have moved on. Far more important to Harry was the upcoming full moon. The first full moon of October was also the last full moon before Harry would need to create his first alchemical work, which meant it was the only opportunity for Harry to collect his own lunar water for the process. Mr Flamel had let slip – perhaps a little earlier than he was supposed to – that students would be required to come up with their own process for the reaction, and Harry intended to do it properly.

For certain purposes lunar water could be collected by one person and used by another, but for most alchemical purposes it was necessary to collect it oneself. So Harry knew that lunar water wouldn't be provided, not like the other ingredients. Fortunately it was easy enough to procure, assuming one had a bit of time and the right equipment.

Technically, Harry thought he could have got away without the lunar water, substituted it for rosewater or a tincture of mugwort instead, but given that he had the opportunity, he wanted to take it. So Harry made his way to Snape's office to get permission for a trip out onto the grounds after curfew to collect his lunar water. He didn't need the permission, since he could have just worn his Invisibility Cloak and snuck out, but he wanted to do it all properly. And if he ended up being caught by Umbridge or another Inquisitor, he would at least have had permission and would have managed to keep his Cloak a secret.

Harry knocked on Snape's office door and waited.

And waited, because apparently Snape wasn't taking visitors.

Despite the fact that part of his job was to take visitors.

Harry sighed and turned around. He could just sneak out, but…

"You may enter," said Snape eventually, just before Harry left.

The door opened and Harry stepped inside.

"You're late, Lupin," said Snape, not looking up from his desk. "It is on the desk. It does not surprise me that you would be so irresponsible—Ah, Mr Potter." Snape had finally looked up. "Forget I said anything. That is a … personal … matter between myself and Mr Lupin. Unimportant. What can I help you with this evening?"

That sounded interesting. Something Snape specifically called out as unimportant was unlikely to be so at all… but Harry had other concerns.

"I, er, well, in alchemy we've got the first alchemical work coming up," Harry said. "I'm not sure if you know but we're supposed to come up with the procedure and everything like that on our own. So for mine, I wanted to use lunar water—but tonight's the last full moon before we're doing the ritual. So I was just wondering if I could have your permission to go out onto the grounds to collect it tonight after curfew."

Snape leaned back in his chair.

"Lunar water, you say? And you know how to collect this?"

"Er, yes, sir—I looked it up. I've got the prism and the right sort of glassware. I've even got the silver chalice. I've never done it before but I think I understand what I've got to do. It's like when we collected autumnal rain in first year, isn't it?"

"Quite," said Snape. He took out his quill and scrawled something onto a piece of parchment. "Your permission. If you would, collect an extra gallon or so for me. I am running low and find myself pressed for time this year."

"Of course, Professor. Thank you!" Harry said. He took the scrap of parchment.

"You may go."

Harry nodded. He glanced down at the parchment to see what Snape had written just in case it had some sort of qualification on it that meant Harry had to use it in a particular way. As Harry exited the office he bumped into someone.

He looked up.

It was Mr Lupin.

"Oh! Sir—I'm sorry, I didn't see you…"

"Quite alright, Mr Potter," said Lupin. "It was my fault."

"You may go, Potter," reiterated Snape.

Harry didn't hang about. He had what he'd come for, after all, and even if whatever 'personal matter' happening between Lupin and Snape was interesting, he didn't want to risk his permission for a night-time jaunt on the grounds over it. So Harry left.

It was only a short trip back through the dungeons to get to the Slytherin Common Room, and Harry saw nobody else on the way before ducking back inside.

Harry spent the rest of his evening in the Common Room editing his homework. Blaise had suggested he take a nap between then and his midnight expedition to collect lunar water, but Harry didn't see the point. Especially since a nap would likely mean he couldn't sleep after getting back. At about a quarter past eleven Harry left largely empty Common Room and made his way out into the castle.

The dungeons immediately outside the Slytherin Common Room were quiet, as they always were, but the rest of the school was eerily quiet. There was usually someone or other wandering about, especially a ghost or two, but that full moon night seemed an exception. Of course, it was too late for prefect patrols, and Harry assumed most of the teachers would have gone to bed, too.

Harry was reminded of his trips under the Invisibility Cloak during his first year, when he'd spent the days over Christmas roaming the castle and looking into its hidden corners and secret places.

Except this time he actually had permission to be out, and wasn't hiding at all. He even had a bag full of equipment, and a signed note from Snape allowing him access to the grounds. Unfortunately, only on a specific date and time… but where permission had been granted once, Harry thought it could be granted again. Especially since Harry had proven himself to be a generally well-behaved sort of student and was a prefect besides.

When Harry reached the Entrance Hall he paused, unsure whether the doors would even be open. He'd never tried to get onto the grounds at night before, certainly never after curfew. There'd never been any reason.

"Oi! What are you up to?"

Harry spun around. He recognised the voice, of course – it was Inquisitor Arlecchino. Harry had a vague idea that the Inquisitors, some of them at least, roamed the school at night looking for… something. Students out of bed, perhaps, although given the Inquisition's remit, teachers doing things they weren't supposed to be doing seemed more likely to Harry. In any case, Harry didn't think Arlecchino technically had the same powers of authority over him as any of the teachers did.

Not that Harry particularly wanted to test that out – he really did want to get his lunar water collected.

"I have permission," Harry said. He got the scrap of parchment with Snape's permission on it out to show Arlecchino.

"Let's have a look at that," said Arlecchino. He took it. "Professor Snape… lunar water under the full moon... dated... eighth of October…" He handed the parchment back to Harry. "Hmm. Everything seems to be in order, then. Do you need an escort out onto the grounds?"

"I, er—no, thank you," Harry said.

"Even with the Black situation? Perhaps that's unwise, Potter," said Arlecchino.

"Black was sighted last week in Mexico," Harry said quickly. "I doubt he's about the grounds. But even if he was, it's important that I collect the lunar water myself. Observers could, er, ruin the alchemical balance of the, um, the reaction." He paused. "I don't think Professor Snape would have given me the permission to go if it was dangerous, anyway. But I really do need to get going, if that's alright—I have to do it under the full moon at midnight and I still need to get set up, see…"

"Well, don't let me keep you," said Arlecchino. "But do be careful—I'd hate to be blamed if anything happened to you out on the grounds."

"Right," Harry said. "I'll, er, bear that in mind. I'll just get going, then." Harry turned and opened the wicket gate set within the larger Entrance Hall doors. When Harry glanced back, Arlecchino was still stood watching him go, but Harry didn't stick around much longer.

Instead, Harry headed towards the lake. Although he didn't require water from the lake itself, the ritual apparently went better when performed near to a natural body of water, so Harry wanted to do it right by the lake.

It was a clear night, the sky cloudless, and with a chill in the air just cold enough to be bracing rather than uncomfortable. A little shiver ran up Harry's spine, but he ignored it. A cloak would have been too hot, anyway. The Moon was bright in the sky, so bright in fact that Harry didn't bother with a light from his wand until he reached a fair distance from the castle itself.

When Harry reached the lake he kept on walking. The best location for collecting lunar water would be somewhere quite far from the castle and other places of human habitation, so Harry would have to avoid the gamekeeper's hut, too. Harry walked along the edge of the lake until he found a suitable place then set his things down on the ground. He had more than enough time to prepare the ground for his little ritual, but even so he didn't want to take too long about it.

"Right, so I need…" Harry mumbled to himself as he rummaged through his bag for the ritual equipment. He would need a prism, which he'd acquired from the student stores earlier that day; a silver chalice, which he'd borrowed from the kitchens; and white candles, which he'd nicked from the dinner table. He set the silver chalice on top of his alchemy textbook – the large, thick tome was perfect as an ersatz table for the ritual – and sat the prism in the cup. He would need to take it out later, but he didn't want it to get dirty while he fiddled with the candle, so Harry thought it would be safer in the chalice.

Next, Harry took out the candles and arranged them in a circle around the silver chalice. He lit them with fire from the end of his wand and then sat back to survey his alchemical circle.

"Not bad," he said. "Not bad." He enlarged the silver chalice with a quick Engorgement Charm, mindful that Snape wanted a whole gallon of lunar water, and that was in addition to everything Harry needed. He'd asked the elves for their largest silver chalice, but even that wasn't quite large enough, and the silver serving bowl they'd offered him wouldn't have fit the ritual.

So he had to make do with the engorged chalice.

Then, Harry filled the silver chalice with conjured water, and sat back.

He didn't even have to place any alchemical sigils, as lunar water wasn't specifically an alchemical product.

Then it was just a matter of waiting. Harry still had a few minutes until midnight, when the power of the Moon would be greatest, so he went over the invocation in his head. At half a minute left until midnight Harry grabbed the prism and held it up to the Moon, angled towards the chalice.

The moonlight had to hit just so, or otherwise…

Harry counted down in his head.

Three, two, one…

"Luna, invoco te! In hac nocte sacra! Ut testificeris, et benedicas hoc rituale meo!"

At first, nothing happened. Then, after a few agonising moments, the prism started to glow. Moonlight flooded the prism, filling it until it spilled out in a strange, ethereal midnight rainbow – and right into the silver chalice. The rainbow of moonlight infused the water sat in the chalice, swirling gently for a few moments before falling still. It sat there glowing softly with a pale white light.

He'd done it.

The lunar water looked just like the textbook had said it would, and he even had enough for his upcoming Salve ritual and for whatever Snape needed it for. The only thing left to do was decant it from the chalice into appropriate glassware, which Harry set about doing right away. When he was done, Harry cleared away the ritual components and made sure everything was as he'd found it, then headed back up to the castle.

Fortunately, when Harry arrived inside, Arlecchino was gone, and there were no teachers or anyone else around either, so Harry was able to get back to the dungeons quickly enough. His dorm mates were all asleep by the time he slipped inside his dormitory, and Harry joined them not long after.

When Monday came it seemed like everyone had moved on – mostly – from Daphne's mural of Umbridge. Harry overheard a few conversations here and there, but as the week went on, they were fewer and fewer. Harry didn't mind, although he knew Daphne was a bit disappointed. But Hogwarts students were fickle, and without a major incident, moved on quite quickly.

Their little group had already suggested several other little bits of protest, but nobody had enough spare time – and at the right times of day – to carry them out. Harry would have done it himself at night, under his Cloak, but even he had far too much to do between his extracurricular activities, his lessons, his duties as a prefect, and all the extra work he had to do to learn occlumency, too.

So Harry spent more time attending to his alchemical coursework. It was by far the subject he considered the most important. It was the only subject that had any direct, short-term, real-world benefits, for one, and it came with the opportunity to learn from Nicolas Flamel himself. That was an opportunity very few people in history ever got, and even if Harry had to share him, that was fine.

Even Professor Dee, whose method and manner of teaching were eccentric at best, provided Harry with a wealth of new alchemical knowledge.

It was all accompanied by that thick, acrid, cloud of green smoke which followed him, but even that didn't ruin Harry's day.

"You'll be making the Salve of Ocular Augmentation soon, this side of Hallowe'en," said Dee in between long, hard drags of his cigarette. "The Salve of Clear Sight. Whatever you want to call it. It's got loads of names. We'll be doing it before Hallowe'en, so not long left until you're blooded alchemists—or until we ask you to drop the class because you've not got what it takes." He took a drag from his cigarette and puffed out a cloud of green smoke. "No pressure."

He put out his cigarette.

"What's unusual about this—for you, anyway—is that we won't be giving you a recipe or a process. Or, not a specific one, anyway. That's because it's different for every alchemist, but also because we want to see how well you actually understand what we're doing here. Like I've said a thousand times already, alchemy is hard. It's weird. It's not just about mixing things together and hoping for the best—you've got to understand it. Higher mysteries, esotericism, all that bollocks. So in the next lot of lessons—mine and Mr Flamel's—we're going to be learning about the ingredients that can be used to make the Salve, and about the incantation you're going to need to craft. Because you have to do that, too." He paused for effect.

"Still listening? Good," he said after lighting a new cigarette. "You won't ever have done this before. Well, I don't expect you to have done it, anyway; none of you lot are especially innovative or clever in your magic. But for the Salve you're going to have to craft a suitable incantation for the ritual process, one that draws on the various bits of symbolism and meaning that you've put together for your specific alchemical work. Got that?"

Harry scratched the back of his head idly. That was... a lot. Easily the most difficult piece of work he'd ever had to do, ever had to contemplate – it blew everything Vector had given them in Arithmancy clear away.

"We're going to help, obviously," said Dee, "but you've got to do the real work. It shouldn't be so bad. If you paid attention to Madame Helix's lessons in first year, you'll be set. If you joined us late and never had those, well... tough luck. Muddle on anyway. Now, today, what we're going to do is discuss weights. Why you'd use an ounce instead of a pound, that sort of thing. Very important. So... get your quills ready." He took a long drag of his cigarette. "This is a me-talking-lecture, so... let's get to it."

Harry already had his stuff ready, of course – Dee was unpredictable, but he usually said something worth writing down at least once in every lesson, so Harry was always prepared. He spent the rest of the double session taking down Dee's words, even when they didn't make sense, just in case he could figure something out later on.

But it was Flamel's lessons which were one of the highlights of Harry's week, and not even the presence of Inquisitors – or Umbridge herself – could diminish them.

"...so, of course, each ingredient required for the Salve of Clear Sight is chosen because it fulfils more than one of our criteria," Flamel said. "Now, if someone would be so kind as to give me one reason we use powdered silver in this alchemical work?"

Nobody offered anything, not even Granger.

Harry thought he knew. It seemed too simple, though, too basic... but as nobody else offered anything at all, Harry stuck up his hand.

"Potter?"

"It symbolises the Moon in its physical, magical, and spiritual aspects," Harry said.

"Excellent," said Flamel. "One point to Slytherin. Yes, of course; we must draw upon the power of the Sun and the Moon in this ritual, and the powdered silver invokes the Moon in its three aspects pertinent to alchemy. The magical properties of silver are helpful, too—healing, purification, all of that good stuff. I'm looking for one more thing," Flamel continued. "One specific reason we use silver, and for this particular alchemical work. Someone guess. If no one gives me an answer—even a wrong one—I'm keeping you all after class."

"Hem, hem," interrupted Umbridge from the back of the classroom. "Is that wise? They will be late to their next lesson, Mr Flamel."

"That, Madam," said Flamel, staring right at Umbridge, "is what we call a natural consequence. So. Anyone willing to make a guess?"

Harry wracked his brain for something else. He could list the normal magical properties of silver, of course, as they pertained to potions and transfiguration and charms, but none of them seemed relevant because Flamel had already covered them. Something specific to alchemy, and something specific to the kind of alchemical work that the Salve of Clear Sight was...

Even Hermione seemed stumped.

For a little while, at least – after a few moments of complete, utter silence from everyone in the room, Hermione put up her hand.

"Yes, Miss Granger?"

"Is it... Is it because silver is associated with feminine energy, with fertility, and the alchemical reaction can be thought of as a kind of rebirth—localised to the eyes?"

It was the least sure Harry had ever heard Hermione be in relation to anything, especially an answer given to a teacher. But now that she'd said it, it sounded right to Harry.

"Yes! Yes, exactly that. Two points to Gryffindor. I admit, this particular feature of the alchemical process isn't on the syllabus, but it is absolutely—"

"Hem, hem," coughed Umbridge again. "If it is not on the syllabus, why are you covering it? We have discussed already what is relevant to your role here, Mr Flamel."

"It's important for Mr Flamel as a teacher of alchemy to help us understand the processes and concepts of alchemy at a level beyond that required by the syllabus, Inquisitor," said Harry, interrupting proceedings. Flamel could have said as much himself, but Harry felt it important that students be seen and heard resisting the Inquisition's rules wherever possible. It was one of the things he and his friends has discussed doing, after all.

And Alchemy with Mr Flamel was a very easy place to do that, as the man spent half his lessons skirting the edges of what the Inquisition considered appropriate anyway.

"Alchemy is one of the esoteric disciplines and to properly understand it—even the bits the syllabus asks for—we need more information." Harry paused. "I know you aren't a student of alchemy," he continued carefully, "but that kind of knowledge really is helpful. We have to come up with our own incantations for the alchemical ritual, and now that I know about the feminine energy of silver, I'm going to have to make up a different one."

"A wonderful defence of the alchemical process, Mr Potter," said Mr Flamel before Umbridge could respond, "but one which is perhaps lost on present company. Moving on, I would like to discuss the properties of orpiment, which is also a key ingredient in the Salve. If someone..."

Flamel continued his lecture. Harry snuck a glance at Umbridge, who sat there toad-like but serene, as if nothing in the world could ever possibly bother her. Unfortunately for her, Harry knew that wasn't quite the case. She would be seething underneath her mask, more than simply put out that a student had spoken back to her – and that the teacher didn't care for her threats.

But he couldn't spend all lesson feeling smug about that, not when Mr Flamel was going over vital information for their upcoming alchemical work. Harry spent the rest of the lesson taking down notes, along with – occasionally – offering an answer to one of Flamel's questions. When Mr Flamel released the class, it was the end of Harry's day, but he still had ideas buzzing around his head for the Salve of Clear Sight, so he went to library instead of returning to the dungeons right away.

He couldn't spend all evening on it, since he had a meeting with Dumbledore later on, but Harry worked up until dinnertime.

As much as Harry would have liked to have spent most of his time on his alchemical work, he couldn't. He had more than enough other things to be getting on with, not least of which were his other subjects. It was OWL year – not that he could forget that with all the teachers going on and on about it at every opportunity – and Harry had a particularly busy schedule. So on Monday, after a hectic weekend, he was dismayed to find Umbridge present in his Defence Against the Dark Arts lesson with Mr Lupin.

The entire school was behind in the Ministry-approved curriculum for Defence as a result of... well, rather a lot of things, as far as Harry was aware, but mostly because of Quirrell. A bit because of Moody refusing to teach the standard curriculum – although what he had taught them was more interesting, so Harry didn't mind much. And because Lockhart was an awful teacher and spent his lessons flogging his travelogues rather than actually teaching.

But that last bit was an unpopular opinion, especially around most of the girls – and some of the boys, too – so Harry kept it to himself.

Still, Mr Lupin seemed to know what he was doing, and he had been marching his classes through the syllabus at a bracing pace, and Harry felt like they were making good progress. Progress good enough that he didn't feel too worried about the OWL. Ironically, though, given the Inquisition's stated aim, Harry was certain Umbridge's presence in the man's lesson would only result in a less efficient and effective experience for everyone involved.

It didn't help that the shabby man looked tired, as if he hadn't slept well in weeks. He stood at the front of the class, shoulders hunched and in almost a slouching posture.

"We're going to talk about boggarts today," Lupin said. "I did have a boggart ready for us all to do a practical session with, but there was... er... I was persuaded not to do that lesson with you all," he continued, glancing over to Umbridge where she sat at the back of the classroom. "So I'll just be doing a demonstration; you won't need your wands today."

Harry sighed.

Fighting a boggart could have been an interesting lesson. Much more fun than listening to Lupin talk about how to defend against one, anyway.

"Maybe after Hallowe'en," Lupin said. "We'll see. Now, I was unwell through a lot of last week, so I didn't get a chance to—"

"Hem, hem," coughed Umbridge. "This is the second time you have been unwell this term, isn't it?" she said. "Am I to understand it is impacting students?"

"I am quite confident that despite my recent illness, High Inquisitor, we are proceeding at just the right pace. I believe I submitted my action plan for the year to you already, in fact, with details on—"

"Yes, yes," said Umbridge, waving her hand. "You did. I am concerned, however, that your recent illness may reoccur. Perhaps—"

"While I am touched by your concern High Inquisitor, I would question whether this is the correct forum for such a discussion," said Lupin. "Again, I am quite confident that I can deliver the curriculum and fulfil my role as an adjunct professor this year—and I would be even more confident if I were able to get through my lessons without continued interruption."

"Hm," said Umbridge. Harry heard the scratching of her quill as she wrote something down onto her little sheaf of parchment. "Continue."

"Who can tell me what a boggart is? Anyone? Don't be shy," said Lupin.

Nobody said anything. Harry assumed most people knew the answer, since it was a basic question – a Dark creature capable of mimicking the fear of whoever saw it. But nobody wanted to draw attention to themselves with Umbridge in the room.

In the end, Harry put up his hand.

"Yes—Mr Potter?"

"Boggarts are Dark creatures that can turn into people's fears," Harry said.

"Quite right. Have five points for Slytherin. Boggarts are considered to be non-human spiritous beings, a category of creature you should all recognise by this point in your schooling. Most people think of boggarts as simple pests, but they can be much more dangerous to the improperly prepared. Can anyone tell me what the best course of action is if you come across a boggart? Anyone?"

Nothing. Nobody moved, except to look down at their desks or elsewhere in the classroom.

Eventually, Hermione put up her hand.

"Miss Granger?"

"There's a banishing spell specific to boggarts, Mr Lupin," said Hermione. "It's called the Boggart Banishing Spell."

"Indeed there is!" said Lupin. "Five points to Gryffindor. So, that's exactly right—the best thing to do if you ever come across a boggart is to banish it. The spell in question is—"

"Hem, hem," coughed Umbridge. "Wilbert Slinkhard suggests two potential courses of action in such a scenario, Mr Lupin—the first being to run away, and the second being to call the appropriate Ministry of Magic department to handle the creature. Is it appropriate to teach children to fight dangerous Dark creatures?"

Lupin paused, rubbed at his chin as if considering what Umbridge had said, and then nodded.

"Yes," he said. "Boggarts are a common pest and the Boggart Banishing Spell—as Miss Granger said—is specific to boggarts. It isn't dangerous—or useful—in any other circumstance. While Slinkhard's methods have their place, I don't think it's very sensible to teach our students to run away from everything they ever encounter. Sometimes it really is worth it to stand and fight."

"The Ministry of Magic does not believe in forcing children to fight Dark creatures," Umbridge said. "Indeed, there is a reason that Wilbert Slinkhard was selected as one of the primary texts for this course moving forward. It seems wholly irresponsible—"

"High Inquisitor, with respect, it is wholly irresponsible to send our children out into the world unable to defend themselves from common pests. In many cases the best thing to do is to run away, but sometimes, we are all unable to run. What then? And, again with respect, the Ministry-approved syllabus includes the Boggart Banishing Spell. It would be failure on my part not to teach it to our students as it is going to be on their OWL exam."

Lupin was always hesitant to cross Umbridge, whether by contradicting her directly or through more indirect means. But on that point, at least to Harry, he seemed defiant. And he had a completely fair point: the Ministry-approved syllabus that Umbridge appeared to have shoved up her arse required Lupin to teach the very spell she had a problem with.

"Be that as it may," said Umbridge, "it is improper to not consider Slinkhard's approach when teaching students as young these. Indeed, I do believe that a proper treatment of Slinkhard's work is included on the syllabus, is it not?"

"It is," confirmed Lupin after a few moments. "Where appropriate my lessons reference Slinkhard, High Inquisitor, but the Boggart Banishing Spell is simple and effective enough that it can and should be taught to all students. If we were speaking about dementors and the Patronus Charm, perhaps, then—"

"Hem, hem," coughed Umbridge. "Are you suggesting, Mr Lupin, that the Ministry is not in control of its dementors? Because the dementors are under the control of the Ministry; it is impossible for our law-abiding students to encounter one. It is, frankly, bordering on sedition to even suggest—"

"There are many more dementors in this world than those appeased by the Ministry of Magic at Azkaban," Lupin said, interrupting. "Sedition is quite far from my intentions, I can assure you. But none of this is relevant to our lesson today. As I have been reminded it is imperative as teachers that we use our time in class efficiently, and this seems like a more … administrative ... issue. May I continue?"

"You may," said Umbridge. "Do be mindful that Slinkhard is also on the curriculum when you continue, Mr Lupin." She didn't sound pleased. Harry had no doubt that she was writing all sorts of things onto her parchment to bring up with Lupin later. Probably even notes to check in on his family or whatever other authoritarian nonsense it was she preferred to do.

Lupin ignored her.

"So, then, as I was saying…" He continued his lecture, covering all of the relevant points – where boggarts were most commonly formed; theories as to how and why boggarts were formed; even case studies from particularly famous incidents with boggarts. Towards the end of the lesson Lupin paused his lecture to pull a big, heavy trunk out from under his desk.

"Alright," he said. "In here is the boggart. As I said before, today's session was going to be a practical one, but instead, I'll be demonstrating the proper use of the Boggart Banishing Spell. We will learn and practise the spell before your OWLs, but not today. Of course, it would be remiss of me to forget that we do not always have to confront entities such as the boggart. It is also possible to simply run away or contact the relevant Ministry body or private pest control service. With that…"

Lupin jabbed his wand at the trunk and an indistinct, fuzzy dark shape shot out of it. Immediately it transformed into a pale, slightly glowing, sphere.

What's that…? Harry wondered. It looked almost like the Moon, but why Lupin would be afraid of the Moon, Harry couldn't say.

"So, as you can see, the boggart transformed immediately upon leaving the safety of its confinement," Lupin said. "Its true form is unknown, but the very fact that it so readily takes on new forms is its own downfall. I appreciate this may be difficult when faced with your own worst fear," he continued, "but the key to casting the Boggart Banishing Spell is to envisage your worst fear as something funny. This will force the boggart to take on an appearance you find funny. That is, you must find some way to make your fear something to laugh at. It is, perhaps, something easier said than done. But I have every confidence in your abilities to do this when the time comes."

He swallowed.

Harry watched. For whatever reason, Lupin was afraid of the Moon – or, Harry supposed, it could be a crystal ball, but even that had its questions. It must have been a big fear of his, for the boggart to manifest in such a way. Harry had no idea what his own boggart might look like – Voldemort? His parents, disappointed? Harry couldn't say. He did know that it would be a hard sell to get him up in front of the class to tackle it, though.

What if it was something embarrassing?

"Riddikulus!" said Lupin, pointing his wand at the boggart. The spell cast with a whip-crack, and the boggart shifted, its features changing. Instead of the Moon – or a crystal ball, or whatever – it was now a comically oversized face. Big, bulbous eyes; a gargantuan nose, complete with nose-hairs; and even a moustache.

Lupin laughed. It was a feeble little thing, barely a laugh in Harry's estimation, but Harry supposed it counted. With a sharp poke of his wand Lupin sent the boggart – now a giant, smiling face – back into the trunk. Once it was safely locked away, Lupin turned around to face the class again.

"There! Not so difficult, is it? The Boggart Banishing Charm can be used, as the name suggests, to fully banish a boggart. When that happens the boggart's form will dissipate—it's like a little explosion of spiritous energy. This doesn't kill it—boggarts are not alive, remember, so they can't be killed—but it does make it reform somewhere else. I didn't want to do that today. Mostly because I plan to use it again in other lessons, for this class and others, but why else might I not want to banish this boggart? Anyone?"

One of the new Ravenclaws put up her hand.

"Yes, Miss Stephenson?"

"Because spiritous energy is messy and you didn't want to get everything dirty?"

"Ah, no," said Lupin. "But that was an interesting guess. Anyone else?" He scanned the room. "Mr Dragonsfoot?"

"Because when a boggart is banished from somewhere like Hogwarts, it's going to reform really quickly. The problem is that you can't decide where, so it could reform in the staff room—where it's easily dealt with—or under a first year's bed. And you just can't tell," said Dragonsfoot in his deep, booming voice that Harry always had trouble connecting with the little wizard.

"That's exactly right! Five points to Hufflepuff. Places such as Hogwarts—a location with about two thousand hormonal, emotional young witches and wizards—are rife with creatures like boggarts. Comes with the territory. This one, though—we know where it is. So that's one boggart that won't end up under a first year's bed. Now… it's near enough the end of the lesson. For homework, I'm going to want two feet on non-human spiritous beings, with at least eight inches being dedicated to the boggart itself. You can hand that in next week. Before you go, does anyone have any questions?"

Harry put up his hand. It wasn't a question, exactly, and he could have done without the answer. He could even have stayed behind afterwards to ask Lupin privately – but the whole point was that Umbridge heard it, along with the rest of the class.

"Mr Potter?"

"Mr Lupin, I just wanted to say that I'm really hoping we can do a practical session with the boggart soon. It seems like an important life skill to have, and as it's even on the Ministry-approved syllabus for the OWL, I'd feel much happier having practised with it before the exam. I don't think anyone," Harry said, "would want to interfere with the Ministry-approved syllabus, after all. I know you said you'd been persuaded not to do it, so fair enough you didn't do it with us today, but I think we'd all prefer if we could get some practise with it before the exam. Especially under proper supervision."

Frankly, Harry would prefer to give it a go on his own – less chance of his worst fears making the morning papers that way – but his statement was performative more than an actual representation of his desires anyway. And it had the desired effect: several others in the class were echoing the sentiment.

Harry didn't look back at Umbridge to check, but he knew she would be seething anyway. Perhaps not openly, as she usually managed to wear that practised saccharine smile in all but the most stressful of circumstances, but she would hate it all the same.

"Ah, yes, Mr Potter," Lupin said. "I'm quite sure we can come up with something appropriate that gets you all a little practise with the spell," he said. "If there are no more questions…?" He paused to check, but there were none. As far as Harry could see everyone had packed away their things, anyway, and were simply waiting to be allowed to go. "Alright, then—get along to your next lessons."

The classroom emptied of students. Harry took a bit of extra time to leave, keen to see if he could overhear anything from Umbridge as he left, but there was nothing. Either Umbridge had nothing to say – which seemed unlikely given what Harry knew of Umbridge – or she was waiting to get Lupin on his own. Although he lingered at the door for a few moments pretending to check something in his bag, Harry couldn't justify any more, so reluctantly left and went about his day as normal.