Don't get up! Saying it ran through Cassia's mind as Potter got up off Black. Don't get up, you had him!

But the boy was already running back to his friends and there was no point in it, because Lupin was already approaching the man on the ground. "Well, well, Sirius, looking rather ragged, are we? Finally the flesh reflects the madness inside."

But he didn't sound spiteful. In fact, he sounded rather... fond.

Cassia shook her head. No, no it wasn't true, it couldn't be true-

But Black was continuing to laugh, and all Lupin did was get closer, smirking a little as he replied. "Well, you'd know all about the madness within, wouldn't you, Remus?"

Then, it happened.

Lupin lowered his wand, practically grinning, before offering Black a hand up. The man took it, the floor creaking hideously as he got up, before pulling Lupin into an embrace.

"I found him-"

"I know-"

"Let's kill him-"

"Sirius-"

Cassia had lived through plenty of betrayals, people promising her things and not delivering, people not treating her the way they should, and people that were supposed to love her despising her instead.

But this one suddenly hit her very hard. Harder, perhaps, than any of that.

"What the fuck?" There was poison in her voice as she spoke, and it was so hard that it made both Lupin and Black turn.

"We trusted you!" She yelled at Lupin. "Actually, he trusted you, more than any of us, in fact!" She jabbed her finger in Potter's direction. "And all this time, y- you've been his fucking friend?"

She wasn't sure why she was so angry. Lupin and Black weren't planning to kill her, after all, and she certainly didn't care about Potter in any volumous capacity that would cause a reaction like this, but- she was just so sick of seeing stuff like this.

Of seeing broken promises and fake love.

"That's not all!" Hermione stood up, shaking her head at Lupin. "I kept his secret- I've been keeping it for months!" She shrieked. "He's a werewolf! That's why he's been missing classes!"

This information would've shocked Cassia not five minutes ago.

Now, she wasn't surprised.

This, however, seemed to stall Lupin, for he turned to Hermione, his eyes a mix of gratitude and confusion. "How long have you known?"

"Since Professor Snape set the essay."

"Oh, he'll be delighted," Lupin said bitterly. "He set that essay hoping someone would see the similarities and find out-"

"Enough talk, Remus, come on, let's kill him!" Black voiced his opinion, speaking savagely from behind.

"Wait-!"

"I DID MY WAITING!" Black looked crazed as he yelled, deafening everybody, with wide eyes and foam around his mouth. "TWELVE YEARS OF IT! IN AZKABAN!"

Lupin looked from him, to the five thirteen year olds before him, and then spoke. "Very well. Kill him."

"What the f-?" Cassia started.

"But wait one more minute, and Harry has the right to know why," he added, speaking over the girl.

"I know why!" Potter finally spoke, anger and betrayal laced in his tone. "You betrayed my parents! You're the reason they're dead!"

He spoke with thirteen years' worth of anger and resentment, despite only learning this fact a few months ago.

"No, Harry, it wasn't him! Someone did betray your parents but it was somebody who, until quite recently, I believed to be dead."

That wording stirred something in Cassia's brain.

"Who was it, then?" Harry demanded.

"Peter... Pettigrew!"

Cassia was shocked.

"You're a nutcase!" She yelled at Black.

"For once, I agree with you," Potter muttered behind her. He raised his voice before shouting. "Pettigrew's dead! You killed him thirteen years ago!"

"No he didn't, I thought so too, until you mentioned seeing Pettigrew on the map!" Lupin fought back.

Cassia frowned. "The map was lying then-"

"The map never lies!" Sirius proclaimed. "Pettigrew's alive! And he's right here, in this room! Come out, come out, Peter! Come out and play!"

"What the fuck are you doing?" Cassia demanded. "Where on earth could he possibly be?"

"Right there!"

She followed Black's finger, getting even more confused as she saw it was pointing at-

"Me?!" Ron demanded. "He's mental-"

"Not you!" Sirius cried exasperatedly. "Your rat!"

Wait, what-?

"How could that be possible?" Cassia asked. "He can't be an animagus, they all have to be registered-"

"Yes, that's true but the Ministry never knew there used to be three unregistered animagi running around Hogwarts."

This information from Lupin stilled Cassia.

What?

"For them to understand, we have to tell them," Lupin said to Black. "We have to, Sirius. Harry deserves to know."

Cassia looked at Potter. He was wordless.

But she wasn't.

"Tell us, then," she said. "I think you're both fucking nutjobs, but tell us and maybe that'll change."

Black looked at them for a second before nodding to Cassia. "And who might you be?"

"I don't negotiate with terrorists," she snapped. "Nor do I tell mass murderers my name."

"Okay, we'll skip that part," Black said. "You can tell me your name once I've told you my story and you realise that I am not, in fact, a mass murderer."

Cassia scoffed. Yeah, right.

"Now get on with it, Remus!" Black snarled as his supposed friend. "I want to commit the murder I was imprisoned for."

There were looks flitting between the five, but Cassia kept her eyes locked on Black. She wanted to hear this.

"Right," Lupin began, sighing heavily. "This story begins with me, and my bite. This never would've happened if I hadn't been bitten, had I not been so foolhardy..."

His face showed pain and regret, and for the first time since he walked through the door, Cassia couldn't find the heart to be angry at him.

Finally, Lupin recovered and went on. "I was very young when I was bitten. My poor parents... they tried everything to cure me, but nothing worked. Back then, there was no cure, and no way to make transforming bearable. The potion I take now, called the Wolfsbane potion, is a recent discovery. It keeps me sane every month, so I am still aware of who I am when I transform, and I am not dangerous."

For a second, Cassia took this in. She wasn't sure whether to launch herself at the man and punch him for selling them this bullshit whilst a killer was in the room, but Lupin seemed to be building up to something here.

It certainly made sense as to why Lupin's clothes were so ragged, or why he had missed so many classes this past year, so for once she stayed quiet, bit her tongue, and let him go on.

"But this was before the Wolfsbane potion was discovered, so back then I became a fully fledged werewolf every month," Lupin winced at the thought. "So naturally, as I grew up, coming to Hogwarts seemed impossible. Parents wouldn't want their children around me, and I would be considered a heavy danger."

Don't feel sorry, don't feel sorry, he's betrayed you, he's friends with Black-

"But Dumbledore was headmaster, and when my father went to him, he was sympathetic," Lupin said rather fondly. "He said there was no reason why I shouldn't be able to study at Hogwarts. No reason I shouldn't be able to be a normal young wizard, going off to school for the first time."

He looked around him, gesturing to the Shrieking Shack. "But, of course, there had to be measures taken to protect both others and myself. I told you months ago, Harry, that the Whomping Willow was planted the year I came to Hogwarts. The truth is it was planted because I came to Hogwarts. This house, the tunnel that leads to it, they were both created for my use. Once a month I was smuggled out the castle and brought here to transform. Of course, the screams I made were heard from the village, and soon there whispers of hauntings spreading around."

The five thirteen year olds he was speaking to were speechless. Lupin, personally, would've put money on Cassia or Harry interrupting by now, but they hadn't.

So he went on.

"But apart from my transformations, I was having the time of my life. For the first time, I had friends. Real, true friends. Four of them. Sirius Black, Peter Pettigrew, and of course, your father, Harry, James Potter."

Harry let out a gasp, and Cassia looked sideways at him. He looked sort of stunned, and for once, she didn't blame him.

"Now, obviously my three friends didn't fail to notice that I went missing every month. At first, I made up some excuses; feeble, really, but I tried. I believed they would desert me should they find out the truth. However, it didn't take them long to, given that James and Sirius were the two best students in the school."

Black concealed a smile well, but Cassia could still see one seeping through.

"But they didn't desert me," Lupin said, his voice becoming more happy. "In fact, they did one thing I would've never imagined. All three of them became animagi."

"My dad too?" One of the five spoke for the first time, Harry being absolutely shocked.

"Yes, of course," Lupin said with a smile. "It took a while for them to master it, of course. I think it was fifth year when all three of them were turning into their animals at will, but when they could, they made my transformations the best times of my life. Soon, we were roaming the grounds and not just the shack, I doubt any student or teacher ever discovered as much about the castle as we did. That's how we came to write the Marauder's Map, actually. We signed it under our nicknames; I was Moony, Sirius was Padfoot, Peter was Wormtail, and James was Prongs."

The other three animals were obvious. The only unknown was James'.

"What sort of animal was-?" Harry started.

"Hurry up, Remus," Sirius growled.

Lupin sighed. "For this whole year, I've been wrestling with myself and my conscience, wondering whether I should tell Dumbledore about Sirius being an unregistered animagus. But I didn't, because I was too cowardly. It would mean admitting that I betrayed Dumbledore's trust as a wizard at Hogwarts, that I took advantage of a privilege I was lucky to have. So, in a way, Snape's been right about me all along. I was sort of helping Sirius."

"Snape?" Sirius snapped. "What's he got to do with it?"

"He's our teacher," Cassia snapped. "And a bloody awful one at that. How do you know him?"

"He was at school with us as well," Lupin explained. "He often fought with James and Sirius, jealous of their popularity, I think, and, well... sometimes it got a bit out of hand."

"So that's why Snape doesn't like you?" Harry frowned at Lupin. "Because your best friends and him hated each other at school?"

"That's right, Potter."

Poppy jumped. Hermione screamed. Cassia went stock still.

Severus Snape was coming through the doorway, a sick smirk written all over his face.

"Oh, vengeance is sweet, how I hoped I'd be the one to catch you-"

"Severus-"

"I told Dumbledore you were helping your old friend into the castle, and look now, here is the proof," Snape snapped.

"Brilliant, Snape," Sirius bit back. "Once again, you put your keen and penetrating mind to the task and as usual, it comes to the wrong conclusion. Now, if you'll excuse us, Remus and I have some unfinished business to attend to-"

He stopped as Snape japped his wand into his neck, and twisted.

"Give me a reason... I beg you."

"Severus, don't be a fool-"

"He can't help it, he's-"

"Sirius, be quiet-"

"Be quiet yourself, Remus!"

"Oh, how nostalgic, quarrelling like an old married couple," Snape smirked.

"Why don't you run along and play with your chemistry set-?"

Sirius stopped as Snape twisted further, almost choking him.

"I could do it, you know," the man said, his voice low and threatening. "But why deny it to the dementors? They're so longing to see you... longing enough to give you a little kiss, in fact-"

"Severus, please-"

Cassia was too frozen in fear or shock or confusion or whatever it was to notice Potter reaching round her, and pulling her wand out her back pocket.

He got it out without her detection and raised it at Snape.

"Expelliarmus!"

The spell was so strong it knocked the man backwards into the rundown four poster, knocking the hangings down in a shower of dust.

"Harry! What did you just do?" Ron exclaimed.

"You attacked a teacher!" Hermione groaned.

"Tell me about Peter Pettigrew," Harry ignored them both, turning his wand on Lupin and Sirius. "What happened between you that night?"

"Peter was the one that betrayed your parents," Sirius spoke, his voice surprisingly even. "He sold them out to Voldemort and when I tried to make him pay for what he did, he cut off his finger to make it seem like I had obliterated him and transformed, heading down to the sewer with the other rats."

"But how did you know he was here?" Cassia demanded. "How did you know he was Scabbers?"

"I saw a newspaper article in Azkaban - Fudge had been visiting and gave me his paper - it was about the Weasley family in Egypt, and-"

"Scabbers was on Ron's shoulder."

Cassia had overtaken him.

Because she remembered that article too. She had seen it on the same day as seeing the Black escaping notice. The story must've been popular and reprinted.

"Yes," Sirius nodded. "And he's missing a toe, isn't he?"

"Holy shit," Cassia was in shock. "You- that's how-?"

"So simple, yet so brilliant," agreed Lupin.

"Wait! Hold on! We still don't even know if Scabbers is Peter!" Ron objected. "That could just be a whole coincidence!"

"Then I think it's time we offered you some proof," Lupin, ever the peacemaker, told him.

Harry looked long and hard at them both, then said. "Show me."

Sirius went for Ron, seizing Scabbers off him, even though the boy put up a fight.

"Give it to him, Ron!"

"What are you trying to do to him-? Scabbers! Leave him alone!"

But Sirius didn't. He took Scabbers over to the piano, a firm grip on him, and set him down, firing a spell at him. However, the rat was too fast and scarpered, dodging more spells from both Lupin and Sirius, running down the piano, over the broken four poster, through a hole in the wall-

Then Sirius finally managed to hit him and a rat tail became human legs, only half of Pettigrew visible and the other half in the other room.

Holy shit-

"Urgh!" Lupin and Sirius grunted as they pulled Peter back through the wall, both of them keeping a wand trained on him.

Ew, was the only thing Cassia could think whilst looking at him.

Most of his head was bald, but he had hair growing round the edges. His face was dirty and clothes in tatters (almost worst than Sirius) and his face was twitching, almost as though he still was a rat.

"Remus? Sirius?" He asked in shock, before launching himself at them. "My old friends!"

He didn't get far. Both Lupin and Sirius kicked him backwards, absolutely repulsed by him.

So Pettigrew turned, seeing Harry across the room.

"H- Harry!" He cried, running to him. "Look at you! You look so much like your father! Like James! We were the best of friends-"

"How dare you speak to Harry?" Sirius snarled, him and Lupin grabbing the quivering man again. "HOW DARE YOU TALK ABOUT JAMES IN FRONT OF HIM?"

"You sold James and Lily to Voldemort, Peter, do you deny it?" Lupin questioned, him and Sirius having cornered Peter now, both their wands trained on him.

"I didn't mean to!" Peter began sobbing, falling to his knees, begging for mercy. "The Dark Lord, you have no idea of the weapons he possesses! Ask yourself Sirius! What would you have done? What would you have done-?"

"I would've DIED!" Sirius roared back. "I WOULD'VE DIED RATHER THAN BETRAY MY FRIENDS, AS, IF VOLDEMORT HAD EVER TAKEN AN INTEREST IN YOUR STINKING FLESH, WE WOULD'VE DONE FOR YOU!"

Peter managed to crawl out underneath the piano and ran to the door, but Harry was quick, and blocked it.

Peter launched himself at him, grabbing on. "James wouldn't've wanted me killed!" He protested. "Your dad would've spared me! He would've shown me mercy- aaaarrrgggh!"

He screeched as he was thrown off Harry again, Sirius and Lupin raising their wands.

"You should've realised, Peter, that if Voldemort didn't kill you then we would! Together!"

"No!"

The shout had come from Potter, and it shocked Cassia. I mean, she knew he was noble to the point of stupidity, but this?

"Harry, this man-" Lupin started.

"I know what he is," Harry said scathingly. "But we'll take him to the castle."

Pettigrew fell to his knees. "Bless you, boy, bless you-"

"Get off me!" Harry snapped as the man attempted to hug him. "I said we'll take you to the castle. After that, the dementors can have you."

At this, Pettigrew froze.

"It's no more than you deserve," Cassia snapped. "You fucking coward."

That shut him up.

"Harry," Sirius said, turning to the boy. "Do you believe us, now?"

He asked almost tentatively, as though he was afraid of what the answer would be.

But Harry was already nodding.

And Cassia had to admit, she believed it too.

The smile that broke into Sirius' face just proved it.

He was an innocent man, whose life had been stolen from him for twelve years.

And the fault was entirely Pettigrew's.