"Ever wondered how the Marauders got the idea to become Animagi? It is usually described as a moment of inspiration from Sirius or James, perhaps the result of a lesson in third year Transfiguration. The reality is that there was more to it, untold. A whole lot more."

A/N: Rated M for future content, pairings slight JP/LE, SB/OC, RB/DM, RL/MD. Hey everyone, this is my first Harry Potter story. I absolutely love the Marauders Era and read so many amazing fanfics I just had to try my own- although mea culpa, please forgive me in that I am not an absolute Potterhead, any world building inconsistencies please message me!

Thank you so much for reading, and welcome to Breaking Form.

Breaking Form

Codename: The Cat is Out of the Bag ("but why would the cat be in the bag?" "Shut up James.")

Sirius, despite his usual persona, needed moments for a Big Think.

Tonight was one of those occasions. He wandered along the shifting corridors, the Disillusionment spell Andromeda taught him cloaking his form, Filch's patterns of patrol safely avoided. He didn't exactly know where he was going, in the way that Regulus used to admit he was "following his own feet"- and Merlin that twinged in a bittersweet staccato, because Family was a common theme of Sirius' Big Thinks. Now the topic was a little more pressing.

Remus Lupin was a werewolf.

His housemate, fellow Marauder and friend was a werewolf, and he had been a werewolf since he was five years old and he was suffering.

Sirius took a moment, stepping out into the cloisters, to reflect on the events of the afternoon.

He and James had noticed Remus getting peaky at regular intervals throughout most of first year. The young werewolf had been adept at changing his story, getting his work done and pulling pranks just so, so that attention slid right past him and his condition... but James had happened to make a stray joke about wolfsbane and Remus' eyes faltered. This morning Remus had showed up to breakfast with a haggard face, bleary and unfocused during Transfiguration, and McGonagall impassively told him to go to the Hospital Wing if he had flu. Remus uncomplainingly picked up his schoolbag, gathered his books in his arms and went, drifting on his feet.

James quirked an eyebrow at his friend. Sirius blinked twice. At the end of the lesson they unanimously trundled along with the other second years before disappearing into the boy's toilets until the hallways had cleared for the next lesson. They were meant to have Runes, but really, who needed to know ancient Celtic- Troll discourses?

"So listen mate, if anyone comes along, just pretend I got a hurt leg from flying this morning and it got worse and you're taking me down to the Hospital wing coz I really can't walk too good."

"Why pretend? You walked into a statue on Monday when Lily Evans turned in your direction, I could whistle her over."

"Did not!" A pause. Then "... Too much authenticity makes us look bad."

Sirius sighed, rolling his eyes and sleeking back his hair. The credibility of the Marauders was indeed Very Important.

Thankfully, they made their way without apparent incident, an old teaching assistant nodding regally as they passed. The giant doors of the Wing loomed ahead, wooden barricades with sweeping stone frames. One was ajar.

James bent his knees, breathed in and cast the invisibility cloak around them. The pair of Gryffindors took each step carefully, passing a couple of occupied beds with the curtains drawn and a table full of medical instruments.

"That's the Ravenclaw Quidditch Captain in there- holy hell he's got a big bruise!" Sirius shushed him. The voices of Gaius and Pomfrey washed over them and, after a moment, a smaller younger voice joined the discourse. Remus.

"How are you holding up young man?"

"I'll be fine sir thank you- The pull of the full moon isn't as bad when there's strong cloud cover."

The Marauders crept closer. Pomfrey was turned to Gaius, one hand held out demonstratively towards Remus. Remus looked very small indeed, gazing up at the Healer with dazed eyes, distracted as though there was someone else in the room calling to him.

"Shall I conjure the chains again tonight?" Gaius spoke to Pomfrey and she nodded primly, but Remus hesitantly spoke up.

"If it's alright with you, the wolf doesn't really like to- well- it hates being constrained, and- and the shack is already confinement."

Pomfrey's eyes widened. "Nonsense Mr. Lupin! Gaius he is a very brave boy but the injuries on him afterwards- The chains help stop him from ripping himself apart- a few months ago it was regularly broken ribs, internal bleeding. Do you know how many bottles of Skele-grow it took me to put his arms back together? THREE! Not glasses, bottles! I insist on the chains."
Gaius rocked back on his heels. Considerate, always moving, formidably bright, he had been the senior physician at Ilvermorny but took part in an exchange program and via route of Durmstrang and Ailingdao had found his way to Hogwarts for two years. Dumbledore frequently gave him leave to discover obscure things and attend Healing conferences, leaving the much more practical Madam Pomfrey in charge. Sirius and James had both been under the impression he was in Spain examining the properties of Manticore dung as an analgesic.

'three bottles?' James mouthed to Sirius 'three bloody bottles?'

Of course it would be that particular part of the conversation James was overwhelmed by. 'werewolf?' Sirius mouthed to James 'a bloody werewolf?'

Honestly, if he wasn't there to keep him on track James would have gone potty long ago.

They watched as Remus stripped out of his robes into hospital attire and clambered into an empty bed. He stayed listless but his eyes focused at the heavens- at the moon, Sirius realised.

They decided that Potions with Slughorn could not be missed in favour of watching their friend's chest rise and fall arrythmically because that was just a little too close to homoerotic for the times. Their class didn't seem to notice that they had been absent too much- Runes had the wonderful property of making everyone drowsy. Except for Lily Evans, who tossed a searching look over at them and nudged Peter. A few minutes later they had exchanged notes enough to say that they had gone to see Remus and tried to give him enough Pepper Up potion to cure his flu but they had gotten the dosage wrong and now he had chronic sneezing of a different sort. Lily had looked back flatly, rolled her eyes, and let it slide. The rest of the day continued apace.

The young Black found himself wandering out onto the grounds. He looked over at the Shack instinctively for a moment, wondering if Remus was in there yet, if he was in pain. After this full moon, they were going to talk.

He didn't know about James, but Sirius had met a werewolf once before at a fellow pureblood's birthday party. It was dressed oddly in loose harem pants and a bow tie, shaggy long hair, totally at odds with the usual stiff formality of pureblood gatherings. They had introduced it like a curio exhibit and he thought it had been made to dance. The harem pants had hidden the shape of shackles around the calves, but they couldn't hide the clinking and rattling, a strange accompaniment to the shuffling dance the beast made.

One of the children had prodded it, when the parents had tired of it, turned away and found Elderwine and point scoring as the new activities. A Mulciber, he thought. The child had asked if there were "more of you". The werewolf had stared, with bloodshot eyes, jaws quivering. "There are few like me" it at last said, with a raspy voice timbered with fear of punishment for answering and fear of punishment for refusing to answer, "because I was bitten and survived. Most bitten die, most alive are born."

The Mulciber child had sneered.

Sirius had had the idea formulating in his head for a while now that Remus might be a werewolf. It made sense, logically, for his illnesses and foibles always coincided with the full moon and Remus in no way appeared to use Dark Potions magic (the other sensible option from Peter). But trying to put together the beast from the birthday party with little shabby Remus, quiet Remus who was gentle and innately polite if untrained- that was the reason for the Big Think.

Remus had to have been bitten because he wasn't a beast as a person. It was a horrible fate for his friend, to be fighting his own body every month and hurting himself.

His feet touched the damp soil that marked 5ft from the edge of the Black Lake. Idly, he cast the countercharm for the Disillusionment Charm and let the soles of his shoes brush the surface of the water. The Black Lake was nothing to do with his family (that he had ever found) but it was nice to pretend that maybe he had a legacy that wasn't malice and madness.

What to do to save Remus?

There was no known cure for being a werewolf. Remus would have to struggle with the transformation one night a month for the rest of his life. Sirius kind of knew that, and that was kind of OK, weirdly, in his head. Remus was so goddamn peaceful the rest of the time that maybe him turning into a giant wolf was like his anger release.

The problem that he hadn't known was how badly Remus was injuring himself. One night a month was fine, but if he had to spend the next week in hospital every time growing back ribs then he'd basically be unable to work and- oh god, what happened to Remus when things like exams came along? What happened when it was time to leave Hogwarts? Would he still have to come back to the Shrieking Shack? Was there another place for him to go and protect the world from himself? What if he hurt himself so badly one time that he couldn't recover or he was so injured there was nothing they could do or-

He considered the way that Pomfrey and Gaius had talked about chains. If there were chains then the wolf couldn't move around to injure Remus and then Remus would be better sooner and things would be OK and maybe the chains were better- but Remus had said that the wolf didn't like confinement and chains made that worse and Sirius kind of understood that feeling of being trapped himself it was a feeling he'd had a lot in the Black households not as literally as Remus though he was sure and surely Remus knew best it was his own body though right?

He stopped dead, heart slamming against his sternum.

The murky waters had just rippled against his foot in the opposite direction to the waves he was making.

Sirius would never say that he was a scaredy cat. However, despite popular misconceptions, he would readily admit to having an entirely appropriate sense of self-preservation.