Disclaimer: I disclaim. That means, anything you recognise is the property of the wondrous JK Rowling.

A/N: Written for the mentors challenge on Omniocular, using the prompt: James or Sirius help Peter with his Animagus transformation.

"No, see, that's where you're going wrong."

James sighed, correcting Peter's grip on his wand for what felt like the hundredth time in as many minutes. It had been like this all night. In fact, it had been like this all night, every night, for the last two weeks.

Initially, Sirius had offered to help him too, but, after the first hour, he'd called Peter a useless waste of magical energy and stormed off, which hadn't been particularly helpful, and so after that, they'd tacitly agreed that James would take over, and Sirius would help by keeping out of the way and offering Remus some company in the library.

If he was honest, James had started to wonder if he was wasting his time, if Peter just didn't have this level of magic in him – but they couldn't leave him behind, it wouldn't have been fair, and so he took a deep breath and tried to swallow his rising ire.

"It's like this – " he said, demonstrating the correct grip on his own wand – fingers together, thumb tightly brought in underneath. "You need a firm grip for Transfiguration – especially for something as tricky as this. Don't you ever listen to what McGonagall says?"

Peter smirked a bit and met James' eye. "Do you?" he said.

"I don't need to," James said tersely, looking away irritably, and just catching Peter's smirk fade a little out of the corner of his eye.

"I'm not doing this on purpose," Peter said tetchily. "I do want to learn how to do it, I'm just – "

James silenced Peter with a smile, then ran a hand through his hair. He didn't mean to get annoyed, but their room was almost unbearably stuffy, and he had homework to do, and Lily might be down in the common room, and he didn't have time for this because the moon waited for no man, even one who had a redhead to gaze longingly at, three feet of parchment still to write on the limitations of shield charms, and a friend who just didn't seem to be able to get this.

He sighed. They'd promised. They'd promised Remus, as soon as they'd found out where he went every month, that they'd help, and they were so damn close –

In truth, it had taken them years longer than he expected to come up with an idea that was really feasible. They'd flirted with theories about somehow trying to mask that they were human – maybe something that would be an extension of the Invisibility Cloak, so the wolf wouldn't know they were there – but that had seemed littered with pitfalls, especially given that the three of them barely fitted under the thing as it was, and Peter nearly always stepped on the hem.

But then, late one night when they'd been awake, waiting for the moon to wane and Remus to return, it had come to them. James couldn't remember who had suggested it first because the conversation had tumbled in a torrent of possibilities – but someone had said it was a shame they couldn't just turn into animals – wondered if maybe McGonagall transformed into a cat to go and check on Remus – and they'd all fallen silent at the same moment and exchanged glances and known – just known – that that was it. The answer.

It was so small an idea, in a way, and James had liked the simplicity, the finesse of it.

Which wasn't to say that it hadn't been tricky to find out how to do it. They'd devoured every book the school library had to offer on the subject – even forged notes from Professor Dumbledore and written off for some more advanced ones – but even those had been annoyingly vague about the actual spell, how one actually went about it, suggesting that the best way to learn Animagus transformation was to find an existing Animagus and ask them to teach you.

The Black library had been a bit more helpful. Sirius had said he remembered some distant aunt talking about an even more distant relative from the eighteenth century who'd spent his whole life trying to master it and never had – that it had become an obsession and sent him quite mad – and so they pored over the shelves there, and came across an ancient tome, covered in half-hearted protection spells they'd barely paused to break.

The incantation – accidere fera – had been scrawled in one of the margins next to a paragraph on 'the moste ancient and dangerous art of Animagary', a cautionary tale about a wizard who had tried the spell without proper forethought and been stuck as a pig forever – but they'd copied out the incantation regardless, before hungrily scanning the other margins for more.

That had been six months ago.

Since then, they'd thought of little else, worked on little else, and James thought, with a rueful smile, that the castle had been very much a poorer place for their lack of pranks and schemes. But it had required a lot of time, thought, and energy to get this far, and in the end, he knew it'd be worth it.

They'd had to be methodical about it, and more careful than they would normally have been attempting a new spell, because all the texts they'd read, whenever they were written and whether they were authored by real life Animagi or not, had contained notes of caution, that whilst turning into an animal was easy, retaining one's mind and being able to turn back again was not. They'd all agreed that having to report to Madam Pomfrey with minor burns from a spell gone wrong and getting the odd detention in return for healing paste was one thing, but having to confess to attempting to illegally perform advanced and dangerous magic, or being stuck with trotters and no mind of your own, was another entirely. For that reason, they'd worked on a counter spell first, one they could use on each other which would force them to turn back if necessary, which would hopefully prevent them being discovered, even in the event of a trotter emergency.

But that was all done, now – there was just one final thing – and that's why James was having difficulty biting back snide comments and hiding his infuriation with Peter's inability.

He sighed again. The full moon grew ever closer, and Remus didn't have a choice. Whether they were there or not he'd face the moon, and James just wanted more than anything for him to know that they hadn't let him down: they'd said they'd find something to help, and they had. They were so damn close – if only Peter would –

But being irritated with him wasn't helping. "Ok," James said, forcing a smile, jiggling his shoulders a little to help himself relax. "Let's just start again, shall we? At the beginning. I'll try and explain it properly this time."

Peter smiled thankfully, and held out his wand obligingly so James could show him again what the correct grip was.

He and Sirius had had no trouble mastering the spell – it was simple enough, an incantation, a fairly rudimentary wand movement – that wasn't the tricky part, despite the hash Peter persisted in making of it.

No, the tricky part was the intent, having the will, the nerve, to actually make the transformation whilst retaining a strong enough hold on your self to retain your mental faculties.

The key to the whole spell, they'd discovered, was that one had to want to become an animal not as a disguise or for some specific purpose, but because it was truly a form in which you felt you belonged. And then the idea of losing your mind to that of a beast became irrelevant, because you weren't becoming an animal so much as changing your form into a different shape.

In the end, it had been Professor McGonagall who had offered them the last missing piece of information they needed, although she'd done so rather unintentionally.

Sirius had become so frustrated with not being able to do it that he'd asked her, in a rather round about way, why so few witches and wizards had mastered it when even advanced and sustained Transfiguration was within most people's grasp with the proper application, and she, James thought, had been so surprised by Sirius' sudden enthusiasm for rigorous academic discussion that she'd dropped them the hint they needed: that to become a wizard in Animagus form, one had to search inside for the animal they already felt they were, and then simply become it.

She'd talked about the immense discipline of mind, force of will and focus it took to do so, likened it to some kind of Muggle meditation, which was why so few wizards and witches had mastered it, a basic lack of patience – but he and Sirius had exchanged a glance and known, instantly, that they could do it. Taken alone, it would have meant nothing, but put together with what they already knew, it was the key to the whole thing. And now they had the key, a whole glorious world of possibilities opened up in front of them.

They'd spilled out into the corridor, making hushed plans to try it that night, properly, and the thought of trying to transform, being so close to achieving what so few had, had made James' blood buzz in his veins. He'd barely heard a word anyone had said to him for the rest of the day.

That night, they'd waited until everyone else had gone to bed, cast a Silencing charm so Remus wouldn't hear them, and had crept back to the common room to try it out.

Peter hadn't understood what McGonagall had said at all, said it sounded airy-fairy and wasn't it more important to focus on getting the spell work right?

They'd ignored him, and flipped a coin to see who would go first.

They'd been scared, of course, though neither of them had admitted it.

Sirius had won the toss, as he always seemed to, even though James had checked his coins for cheating charms, and elected to try first. James had held his breath as Sirius had deftly performed the spell, and muttered the incantation to the ceiling.

They'd waited.

Nothing had happened, and then Sirius had closed his eyes, taken a deep breath, and tried again, and in the next second, he'd disappeared and a dog had stood where he had, its legs trembling slightly and a dazed expression on its face, as if it didn't quite know what it was doing there, couldn't quite believe what had just happened.

Peter had giggled nervously in the corner, clapped his hands over his mouth in surprise, and James hadn't known quite what to do. He'd thought about – dreamt about, even, this moment, and how he would react. He'd thought he'd cheer, maybe, that there'd be celebration, and though his chest had swelled with pride and gratefulness that finally – finally they'd done it, and he'd felt as elated as he had done after any Quidditch match, he hadn't been quite able to summon any words to mark the occasion.

The dog in front of him had taken a cautious step across the rug, then another, and then started to look a little less dazed, and turned round to look at its own tail. And then it had let out an experimental murmur of a bark, and leapt after it, turning full circle a couple of times before coming to rest in front of them again, panting slightly but looking, impossibly, as if it were smiling.

"Sirius?" James had said, and the dog had nodded. He hadn't been able to contain his grin, then. He'd muttered something about always knowing Sirius was a bit of a dog, and Peter had sniggered, and then asked if he wanted to try too. James had said yes immediately – anything Sirius could do….

He'd taken out his wand and closed his eyes, just as Sirius had done, letting the common room and all of his other thoughts fade away into nothingness.

Animal, he'd thought, what animal….

And as he'd muttered the spell, a force, huge, and cold had flown through him, and it had come to him as if he'd always known it:

I'm a stag.

The hooves, he admitted, had taken a little getting used to.

The antlers no less so, since they were at exactly the right height for getting stuck on the candle brackets on the walls – but, after a moment, he'd adjusted, and something about it had felt marvellously… right.

All of which he'd tried to explain to Peter, and all of which had been met with a curled lip and a bemused furrow of his brow.

"It's just – you have to – I don't know – feel it, or something. It's like McGonagall said, it's inside you already – you're just – I don't know, letting it out."

Peter nodded, although he still looked wholly unconvinced, and James didn't really understand why. Magic like this, that came from within, that was an echo of your very magical being, an extension of it, given form and resonance in the real world, was his very favourite kind. And Peter, though he lacked their big ideas, maybe, was very able, and James knew he could do this, if only he really tried, really craved being able to do it.

"Do you want to have a go?" James said, wincing a little at the thought.

Peter squared his shoulders and nodded, although his wand arm trembled just a little. "So I just – " Peter demonstrated the wand movement, and James nodded, smiled encouragingly. " – say the words, close my eyes and then try to feel inside what animal I am. And then they'll be a kind of cold feeling, and I'll be it."

"And if anything goes wrong," James said, "I'm right here, and I know the spell."

Peter nodded, tensing his jaw and pursing his lips, gripping his wand so tightly that his knuckles turned white. "Ok," Peter said. "I'm going to try it."

"Ok. Just – take your time."

James wondered if he shouldn't have said something more encouraging – you can do it, or something, but he wouldn't always be there to offer words of encouragement, and Peter needed to do it on his own.

Peter stepped away a little, into the centre of the room, his hand still shaking a little, but his face was set and determined. James heard him take a deep breath as if he fully expected it to be his last, and then he closed his eyes.

Minutes passed – James didn't know how many. It was so many, though, that he got bored of waiting for something to happen and drifted off into a daydream about the upcoming match against Hufflepuff, wondering if a new formation – where the beaters hung back and lobbed the bludgers long and low, theoretically making more room for the chasers and seeker to do their thing and not leaving the keeper as exposed – would work.

And then he'd even had time to get bored of that, and instead, he'd written the first four paragraphs of his essay on the limitations of shield charms in his head.

He looked up. Peter was still standing stock still in the middle of the room with his eyes closed.

He wondered how long it had been since Peter had been this quiet for this length of time, since normally he couldn't abide silence. Even if he wasn't the one doing the talking, Peter liked for there to be conversation in the room, and he'd always start something if they were quiet for too long, even if he didn't really want to contribute to the discussion.

He was just about to ask Peter if he was ok, when the atmosphere in the room changed, and his skin tingled. James held his breath. He didn't want to jinx it even by thinking that Peter had finally mastered it –

He completed the wand movement, muttered the incantation, and then, all of a sudden, Peter disappeared.

For a moment, James wondered if Peter had accidentally Apparated, or done something else unintentionally to make himself invisible, but then movement on the ground in front of him caught his eye.

A rat stared back up at him from the rug, shaking slightly on its paws.

"Peter?" James said. The rat blinked at him, and then eyed the room slowly, cautiously, taking it all in – and James knew what he was doing, adjusting to his new perspective on the world. He laughed – he couldn't contain it. "You did it!"

Peter experimentally scurried across the rug to the hearth and back again, and then re-appeared in human form, looking rather startled, but pleased with himself all the same. He let out a long whistling sigh, and then smiled tentatively. "That was amazing," he said.

"I know."

James' heart soared. He couldn't help picturing Remus' face when they told him that he never had to be alone with the moon again, thinking of everything they'd been through to get to this moment, and knowing, just knowing, that it'd all been worth it.

Peter met his eye uncertainly, and shifted from foot to foot on the rug. "Thanks," he said, "for all your help. I know you've got better things to do."

"Don't mention it. S'what friends are for, isn't it?"

Peter grinned, and the door swung open. Sirius came in, shot them both a vaguely amused glance and then threw himself down on his bed. "Still at it?" he said. "At this rate, whatever your form is, it'll have grey fur."

James raised an eyebrow at Peter in a silent go on then, show him, and Peter smirked. He closed his eyes, and this time, he did it near instantly. Sirius sat up straight and, when Peter reappeared, met his eye. "You finally got it, then?" Peter nodded. "Well it's about bloody time," Sirius said, although the grin he was sporting rather belied his words, and his vaguely derisory tone.

For a moment, the room was quiet and still, and they looked at each other, silently acknowledging their achievement, and what it would mean for all of them, but one of them in particular.

Animagi. They'd done it.

James cleared his throat. "Well come on then," he said, making for the door. "Let's go and find Remus."

A/N: Thanks for reading : ). Reviewers get a private lesson of their very own, from their favourite Marauder, in a subject of their choosing ;).