Disclaimer: As you all know, I don't own the moon.

Or Harry Potter.

I'm working on clever disclaimers. I'll get back to you in a few years with some wit.

Harry pulled his Invisibility Cloak tightly around himself as he crept past another corner, eyes flitting from the dark corridor ahead of him to the Marauder's Map and back again. Something niggled at his stomach when he glanced at the name he was currently trailing around the empty hallways.

As curious as he was about Professor Lupin's recent nightly outings, he'd managed on previous nights' inspections to stow the map away out of respect before tracking the professor's destination.

Tonight, however, he was determined to follow through with his investigation.

Ever since the professor's midnight excursions had begun, he'd been looking stranger and more tired than Harry had ever seen him. His movements were different, sometimes clumsy – Harry would now be surprised to see Lupin walk more than twenty feet without stumbling. He had also taken to sitting quietly at his desk during class, staring blankly at walls and empty desks for long periods of time with a peculiar glimmer touching his eyes. Even Hermione expressed concern for the distracted Defence teacher.

Initially, Ron and Harry agreed that the potion Snape had been brewing for Lupin must be affecting him badly; Snape had obviously made sure it would work slowly and progressively, so as to divert suspicion from the Potions Master's intentions, and soon Lupin would be found somewhere unconscious – or worse. Upon Hermione's insistence, though, Harry had finally conceded that Lupin was far too intelligent not to notice if a fellow staff member was poisoning him.

Deciding that all of this must have something to do with Lupin's odd disappearances from his office every night, Harry had resolved to help in any way possible.

And if helping meant spying on his favourite professor for an hour or so, then his conscience could take a leap off the astronomy tower.

He carefully wiped the map blank and tucked it into the back pocket of his jeans, wanting to pay closer attention to his dark surroundings. He was close enough to see the professor now, and it certainly wouldn't do to trip over some unseen obstacle and give himself away.

They were weaving their way through a very seldom used wing of the castle, where Harry was quite sure he'd never been before. It seemed as though Lupin was making unnecessary side trips, sometimes ducking into narrow hidden staircases and doubling back before taking another turn and continuing in the same direction as before. They never remained in the same corridor for longer than ten seconds.

Harry supposed he was trying to ensure that no one followed him. He quickly gave up on trying to remember the complicated route they were taking, as Lupin was moving faster now and Harry had to concentrate in order to keep up and stay silent at the same time.

They carried on this way for at least a half hour, with Lupin whipping around corners, up and down stairs, and casting nervous glances behind him while Harry jogged along as quietly as he could manage. Finally the professor stopped in a particularly narrow corridor, and Harry paused on the staircase leading down to the short hallway. Squinting into the darkness, Harry saw only one door to his left, where Lupin was now standing. At the end of the corridor was a hulking statue whose shape Harry couldn't quite make out. He noted mentally that the only escape route was the way they'd arrived.

He looked back toward Professor Lupin, who had one hand on the solitary door and was glancing around the dark hallway suspiciously. Harry's breath caught in his throat as the professor's eyes settled somewhere just beyond him, but Lupin apparently felt the area was secure and turned to the door. He tapped out a complicated sequence on the wood, keeping the noise so minimal that Harry almost missed it. He crept slowly down the stairs and into the hallway, now only feet away from the professor.

Harry tensed when the door swung open while Lupin, conversely, seemed to relax a great deal.

"Remus, you great prat," came a harsh whisper from within, and Harry bristled at the insult on Lupin's behalf. "You don't need to go on with that ridiculous show. No one else ever comes down here."

Harry inched closer, wishing he could get a proper look at the shadowy figure in the doorway. Was he about to discover the cause of Professor Lupin's strange behaviour? He had to strain his ears to hear the professor's reply.

"I'm only being careful. I wouldn't want Dumbledore to–"

Harry jumped slightly as an irreverent snort echoed through the quiet corridor.

"Dumbledore's never stopped me coming here before."

Now Harry tensed again; what was going on that Dumbledore might want to stop? Worry gnawed at him as he eyed the professor's still unguarded posture.

"He waved at me in the village today," the stranger continued. "Had a funny look in his eyes. I wonder if he really knows about this; he does seem to know everything..."

Lupin sighed. "He doesn't, really. Not everything." And suddenly he stepped inside and the door closed behind him. Harry swore under his breath. He'd had no chance to sneak in behind the professor, and it was impossible to hear what they were saying inside while they continued to whisper. He huffed in frustration and slid down the wall opposite the door to wait for a hint at what was going on.

He looked up at the stairs, wondering if any more strangers would appear. How many people were already inside? And what was happening in there every night to throw the professor off so much?

Harry sighed again, running through as many ideas as he could think of. Only a few made any sense, so he studied them more carefully:

1. Lupin was teaching night classes, in much the same way as he'd been helping Harry work on the Patronus Charm.

But why wouldn't he want Dumbledore to know? Harry wondered. Surely that's the kind of thing Dumbledore would encourage. Can't be right. Next.

2. Lupin had not, as he'd suggested, been 'taking delivery' of magical creatures for his lessons, but was trading for them illegally as Hagrid had done for his dragon egg in Harry's first year.

Impossible, Harry thought firmly. Lupin's not stupid enough to do something like that in the castle, and there's no secret passageway out of Hogwarts here on the map. And anyway, Professor Lupin wouldn't lie to us. I think. Next.

3. Lupin and other staff members were meeting in secret to complain bitterly about their least favourite students and wax poetry about the brilliant ones like Hermione. Dumbledore would not approve.

Alright, that's just ridiculous.

Harry frowned and squinted at the door and gripped his wand, wondering if enough concentration would allow him to see past it. For one excited moment, he thought he had done it, but as he rubbed his tired eyes he realized the new colours clouding his vision were simply a result of staring too hard.

CRASH!

Harry sprang to his feet, barely clutching his Cloak around him and searching for the source of the noise. Everything in the corridor was still, leaving only the occupants of the mysterious room as the culprits.

BANG!

Harry's mind was made up; he'd have to go in. If the professor was in danger, and it sounded as though he was, then secrecy be damned. He reached for the doorknob, took a deep breath, and –

–flattened himself against the wall once more as two figures swept down the staircase and into the corridor. Harry shuffled toward the statue to make room for the newcomers. One of their wands was lit, revealing the face above it.

Snape.

It was indeed the potions master, and the thunderous expression on his face made Harry's insides churn.

"I've told you before, Headmaster," Snape intoned severely, "that Lupin was up to something. And here's the proof. He's been disappearing to this wing of the castle every night for the past week. If this intruder he's been meeting turns out to be Black –"

"We shall see, Severus." Harry jumped at Dumbledore's voice. He sounded worried to a degree which Harry had never heard.

Harry's heart was pounding as his mind raced to catch up with the professors' words. Black? Sirius Black, with Professor Lupin?

He was left no time to consider this outlandish thought; Snape reached for the door, wand held aloft and sneer firmly in place. Harry held his breath and sneaked closer to the door, placing himself in a position to see inside the room.

Snape turned the handle…

And with a flourish, he pushed the door open, allowing it to slam loudly and dramatically into the stone wall. A broad wave of his wand illuminated the torches around what seemed to be an abandoned classroom. Snape and Dumbledore stepped through the door simultaneously and Harry heard at least two people swear. Loudly.

"What is this?" hissed Snape.

Harry grabbed his chance, slipping in past the stunned professors and crossing noiselessly to the other side of the room before following their eyes to the desk by the blackboard, where Professor Lupin was standing ramrod straight with flaming cheeks and slightly mussed hair. A shattered muggle globe and an overturned armchair accounted for the noises that had echoed into the corridor. It took Harry's brain slightly longer to compute the young witch sitting on the desk behind Lupin.

Her face was defiant as she glared back at Snape, and her short brownhair was even messier than Lupin's.

"Not, I suspect," Dumbledore spoke up, eyes twinkling, "Sirius Black."

Harry, already hopelessly confused, struggled to identify a reason for both Lupin and the woman to flinch so noticeably at the mention of Black.

"Indeed." Snape's lip was curled so tightly Harry was sure it would dry out and remain there forever.

A horribly awkward silence stretched out, with Dumbledore seeming to be the only comfortable person in the room. He was, in fact, rocking back and forth on the balls of his feet with his hands clasped behind his back. Harry thought he heard low, cheery humming.

Finally Lupin, still flushing madly, cleared his throat. "Headmaster, I think I owe you an apology."

The witch abandoned her glaring at Snape to look sharply at Lupin. Dumbledore chuckled.

"My dear boy, whatever for?" His eyes carried on twinkling. He had the breezy air of someone who was thoroughly enjoying himself.

"Yes, Remus, whatever must you apologize for?" The witch added, looking slightly annoyed. Harry wondered if Lupin had offended her somehow.

Lupin looked even more worried now, glancing pleadingly up at the woman on the desk before attempting a reply to Dumbledore. "Well, for–you know, erm–sneaking around and–well, I–" Lupin struggled on like this for a long while until Snape interrupted him.

"For fraternizing," his sneer deepened as he spoke and he fairly spat the word at Lupin, "with former students, perhaps?"

Lupin's skin was now terribly pale underneath his mottled blush, but the witch's face was coloured with anger rather than embarrassment.

"You might have noticed that I'm notyour student anymore, Snape." She said coldly. "And I've been working 'round the clock in Hogsmeade to help protect you and everyone else in this castle."

Snape arched an eyebrow. "Oh, is that what the two of you were doing just now? Well, I must admit I fail to see how anyone should benefit from your schoolgirl exploits, but then they do say the Auror program has been heading south recently."

He paused to allow the witch a splutter of indignation, then continued with increasing derision. "And from whom exactly are you, ah…protecting us? Your dearest cousin, I believe?" The witch's face now matched Lupin's, and the professor's fists were clenched and shaking as Snape pressed on. "Perhaps you wish me to think it a coincidence that the two of you have…come together at this particular point in time, but I am not so foolish. When I find out how you're helping Black–"

The witch clattered onto the stone floor, striding over to Snape with her wand levelled at his nose. Harry would have thought the gesture ruined by the fact that she stumbled slightly on her dismount of the desk, but he was distracted by her rapidly changing hair colour – the mop of light brown was now bright red and standing on end.

"If you're actually suggesting," she whispered dangerously, "that either of us would help him, you ought to be locked up right next to him."

Harry, who had felt a blush spreading across his own face with the realization of just what they'd interrupted, forgot his embarrassment momentarily in order to nod along with the witch's defence of herself and Professor Lupin. Hadn't the professor been helping him since they met? He was the best Defence Against the Dark Arts teacher Harry had ever had; he'd even been friends with Harry's parents! Harry trusted him, and Snape certainly wasn't about to change that.

As for the woman…well, he'd reserve judgement for now. (Sirius Black's cousin?)

Dumbledore spoke up, pre-empting Snape's retort. "I think I am right in saying that no one in this room needs locking up." He smiled benevolently at everyone, but Harry was unsurprised to see that none of them wavered in their anger. Dumbledore went on, "Miss Tonks, your hair seems to be slightly unsettled. Perhaps you would oblige a silly old man? I rather favour the pink…"

Tonks, not taking her eyes off of Snape's scornful expression, scrunched up her nose in what Harry assumed was distaste until her hair changed colour again, bubblegum pink spreading slowly from the roots outward. Dumbledore beamed.

"Excellent! Now, Remus, if you would kindly escort Nymphadora upstairs?"

Lupin's mouth was pressed into a thin line and he kept his eyes steadily fixed ahead of him, looking at no one as he nodded toward Dumbledore and swept past the still-smiling Headmaster. A firm hand on the small of the witch's back guided her out the door with him. She stumbled again, throwing more angry glares at Snape over her shoulder. With a polite wave to Dumbledore, the door closed behind the odd couple and silence reigned once more for a few minutes.

Harry shuffled uncomfortably.

"I seriously hope, Headmaster," Snape finally ground out, now positively growling, "that you will not allow this indiscretion to go unpunished."

Dumbledore dropped into an empty desk, pulling out a packet of lemon chews and picking through them before replying with a broad smile, "The day I punish love, Severus, is the day we have lost the war against hatred."

"Love?" Snape snapped incredulously, "You call that love? Nymphadora Tonks is barely more than a child, and Lupin is hardly fit for anything of that sort."

Through his own discomfort at such a discovery about Professor Lupin, Harry couldn't help but feel indignant on Lupin's behalf at the open disgust Snape expressed. As if he was worthier of love than Remus Lupin.

"Nymphadora Tonks, you will remember, is very nearly a fully-trained Auror," said Dumbledore calmly. "And Remus Lupin–"

"Is a werewolf. A filthy, untrustworthy–"

"Enough!" Dumbledore cut off Snape's tirade neatly and sternly, but Harry's mind was already spinning along with Snape's temper. A werewolf? Professor Lupin is a werewolf? He wasn't familiar enough with the Wizarding World to understand all the implications attached to this astounding piece of information, but he knew it was huge. Beyond huge, even.

I guess that explains why he's always looked so exhausted…and why he's too ill to teach once a month. And what his boggart was – it must have been the full moon!

Harry forced his mind back to the present, still slightly numb with the shock of more information than he ever really needed about his Defence professor.

"Remus Lupin," Dumbledore was saying, "is among the best employees I have had the pleasure to hire in my many years at Hogwarts, as well as one of the most caring and well-intentioned individuals I have ever met. As I believe I have made clear to you on numerous occasions, Severus, I trust him fully and completely."

All doubt was wiped from Harry's mind with this testimony to Lupin's character. He was suddenly proud to have grown close enough to the professor to receive private lessons from him, and reminded himself to thank Lupin properly next week. Maybe it wouldn't be so strange to get to know the man…

Snape fumed as Dumbledore – absurdly – popped a lemon chew into his mouth.

"Mmm. Delicious, as always," Dumbledore said lightly.

A sniff and a curt nod from Snape signalled his departure. A few long minutes after Snape's billowing robes had disappeared into the empty corridor, Dumbledore rose as well, stowing his packet of sweets away and sweeping serenely toward the open doorway.

"Good night," he said cheerfully over his shoulder, and he gently pulled the door closed behind him as he left.

It took Harry a moment to realize that he was the only one left in the abandoned classroom.

He was still wearing his Invisibility Cloak.

"I know what Professor Lupin's been doing."

Ron and Hermione were looking at him eagerly. They'd found a quiet corner in the Gryffindor common room after classes the next day in order to discuss Harry's findings. Harry wasn't entirely sure he wanted to have any discussion at all.

"And?" Ron was leaning forward conspiratorially, his face set as if he was expecting dire news of Lupin's criminal activity or imminent demise.

"Erm–"

"Have I missed anything?" Harry jumped as Ginny plopped down in the armchair across from him and leaned in along with Ron, who looked askance at her.

"And what are you doing here?"

"Ginny's been just as worried as we have," Hermione answered for Ginny, glaring at Ron as if he'd personally offended her.

"Professor Lupin is my teacher too, you know," Ginny added simply. "So what's going on, Ha–" she broke off momentarily and swallowed before ploughing forward. "–Harry? Is he alright?"

Harry blinked at the slight flush that coloured her face when she spoke to him, but shook it off and steeled himself for what he was about to report.

"Well," he hedged, still uncomfortable with the revelations he'd uncovered. "First off, he left this behind."

Harry pulled Lupin's cloak out of his bag – he'd picked it up from the desk where Lupin had apparently discarded and forgotten it the night before.

Hermione gasped and Ron looked grave.

"You mean he's…gone?" Ron asked quietly.

"Don't be silly, Ron," said Ginny, "I've just come from Defence, and the professor was fine. Although he did blush a lot while Tara Jenkins was going on about her favourite colours, and he dropped an empty Grindylow tank when someone mentioned… was it Healers? No, no, Aurors, I think. Does that make sense, H – Harry?"

Harry had to think for a moment about why Lupin would be embarrassed at the mention of colours, but then he nodded slowly, remembering the woman's unusual hair. A bit of a stretch, perhaps, but obviously the professor was somewhat touchy at the moment.

"Tara Jenkins and Healers. Or Aurors." Ron looked unimpressed. "I don't get it."

"Not Tara Jenkins," said Harry with a sigh, "colours. And Aurors. Professor Lupin and – well, I'll start at the beginning." And he told them everything, trying not to stumble or blush too much when he got to the appearance of the woman with Lupin. It didn't help that Ginny and Hermione were giggling uncontrollably from that point on.

Harry was relieved to hear the three others protest Snape's accusations of Lupin and Tonks helping Sirius Black; it was good to know he wasn't the only student who truly saw past Lupin's shabby exterior and trusted him at heart.

Still, Harry hesitated when he reached Snape's angry outburst about Lupin, wondering whether he should explain the reason for the Potions Master's disgust (after all, Snape didn't need any particular reason to be disgusted with anyone; no one would question him).

"He's just jealous," Ginny grinned, and Hermione nodded.

"Go on, Harry," she urged. "What did Dumbledore say?"

"Dumbledore defended them," said Harry slowly, deciding on the truth, "and Snape interrupted him to say that…that Lupin couldn't be trusted because…" He took a deep breath. "Because he's a werewolf."

He said this last word so quietly that he wasn't sure at first if the others would hear it, but Ron jumped to his feet; his eyes were wide with shock and his cheeks mottled red with anger.

"He's a WHAT?"

"Shush, Ron!" Hermione grabbed his elbow and pulled him back down, glancing nervously around the room as a few curious eyes turned their way.

Ginny simply stared at Harry, her mouth hanging slightly open.

"Did…did Dumbledore know?"

Harry nodded. "And he still defended him. He said Professor Lupin's…well, I don't remember exactly what he said. He sort of laid it on a bit thick to be honest; but he basically said that Lupin's one of the best people he's ever met, and I agree. If Dumbledore doesn't have a problem with the werewolf thing, then neither do I," he finished, trying to put some finality into his words.

Hermione looked at him apologetically, and Harry thought he saw tears in her eyes. "Oh, Harry, I should have told you. I knew you wouldn't care, but I just couldn't risk it; it wasn't my secret–"

"You knew?" Ron was aghast. His voice was shrill and Hermione had to shush him again as he spluttered incredulously. "You knew, and you didn't tell us? And why would you tell Harry, but not me?"

"Because I knew you would react like this!" Hermione huffed.

"Of course I'm reacting like this! He's a bloody werewolf!"

Before Hermione could reply, Ginny smacked her brother's shoulder. "Will you shut it? We all know Professor Lupin's a fantastic teacher, and he's probably been taking the Wolfsbane Potion –"

"Of course!" Hermione interrupted her. "Wolfsbane Potion! That must be what Snape's been making for Professor Lupin!"

Ginny nodded thoughtfully, and Harry wondered how much information Hermione had been sharing with the younger girl.

"Sorry," he said, "but what's Wolfsbane Potion?"

"It keeps a werewolf's conscious mind intact during transformations, so the wolf never takes over completely," Hermione explained. "A werewolf who drinks it would be like an animagus at the full moon – they would look like a wolf, but they'd still be the same person inside. It means Professor Lupin is safe when he transforms," she finished.

"Oh." Harry wondered if his amazement at everything new in the Magical World would ever wear off. He hoped it didn't. "So why does it matter at all? If he's safe, then no one should care what he is!"

"It's not that easy," said Ginny sadly. "There's already so much prejudice surrounding werewolves that not many people care whether they're actually dangerous or not. And Dad says the Potion is expensive anyway, so not many people get to take it. It's amazing that Dumbledore hired Professor Lupin at all, because most people would run the other way if they knew."

Hermione nodded. "There are some horrible laws being examined in the Ministry of Magic right now that would make it impossible for Professor Lupin to get work. They want to make it illegal for anyone to hire a known werewolf, and they're going to require all werewolves to register with the Ministry."

"But that's ridiculous!" Harry burst out. "How are they supposed to survive if they can't get a job?"

He didn't like the silence that followed.

"I reckon that's the idea," came Ron's quiet reply, and Harry was glad to see that he looked slightly disturbed. Whatever intolerance was ingrained in Ron, perhaps he could still get past it.

"So," chimed Ginny, clearly trying to brighten the mood, "Professor Lupin's in love with an Auror."

"No one said anything about love," Ron grumbled.

"Not just an Auror, a Metamorphmagus," Hermione enthused, ignoring Ron entirely. "They're very rare. I can't think of any other way she could change her hair on demand like that without using her wand."

"She's also Sirius Black's cousin," Harry said woodenly. He couldn't help being slightly wary of anyone related to a mass murderer – particularly one whose to-do list was topped by Harry himself.

"So?" Ginny raised her eyebrows. Harry noted absently that this was the most she had ever spoken in front of him. "Ron and I are related to the Malfoys, but we're not about to run off to the Slytherin table and simper over his stupid arm."

"Yeah, I know, but – hang on, you're related to Malfoy?" Harry was getting tired of unexpected revelations.

"We don't talk about it," said Ron sourly. "Anyway, you said Lupin's girlfriend is an Auror? D'you think maybe we could meet her? I've always wondered what the training is like." His face brightened suddenly. "Hey, maybe she could put in a good word for us, Harry! This is brilliant!"

Harry wasn't sure how to respond, rather taken aback by Ron's sudden change of attitude.

"I know a few female students who won't be quite so thrilled the professor's got himself a girlfriend," said Ginny wryly. Hermione snorted and looked pointedly at a group of fifth-year girls giggling over their Defence Against the Dark Arts textbooks. One of them was holding a small stack of pictures, and they didn't really seem like they were studying. Harry wondered if the girls were taking pictures without the professor's knowledge or if they'd simply brought their cameras to class. He wasn't sure which idea was worse.

"You don't mean to tell me all the girls around here fancy him too?" Ron groaned. "What exactly is so attractive about bloody Defence teachers?"

Harry laughed, remembering the bumbling excuse for a professor they'd had last year; Lockhart's nauseating smile had blinded a lot of girls to his complete incompetence.

"Nothing at all," snapped Hermione, but Harry could see the faint blush tingeing her cheeks.

"Oh, please," Ron looked slightly queasy, "don't you two start mooning over him as well." He blinked, belatedly regretting his choice of words.

Ginny was the first one to start laughing, and they all joined in eventually. On a night when they could discuss a werewolf's private life and then draw up a list of his most attractive qualities, nothing could be taken too seriously.

First story submitted in a loooong time. I actually wrote this while wandering around Europe this summer with my parents. Sitting in a cafe in Dubrovnik with a PlayBook is probably one of the best ways to write. :)

Originally, the gang actually did draw up a list of Remus' most attractive qualities, but I cut that bit because it made me vomit a little. I'm just too lazy to fix the last line...

This could expand into a multi-chapter AU, but until I have time to undertake something like that, it'll just stand alone. Hope you enjoyed it!