Calla was shaking against Harry's shoulder, hands clenched into fists. She couldn't believe this had actually happened, that Buckbeak was - was dead and they couldn't do anything about it, anything at all! "I can't believe it," she whispered, sobbing. "How could they?" She stood with the others, all of them transfixed with horror. He was gone. A life taken, just like that. "It's so wrong," she said, shaking. "It's all so, so wrong!"

"I can't believe they did it," Hermione was saying, shuddering and very pale. "They really killed him."

"We should go," said Harry gently, and they turned numbly, walking slowly and miserably back up to the castle. Calla's stomach was churning; everything just felt wrong, wrong, wrong. She thought she really would be sick in a moment, and paused, squeezing her eyes shut. Not now, she thought. Please not now.

She forced herself to keep on walking, with the night falling dark around them. The castle was in sight, and Calla wanted nothing more than to run into its warmth and never come out again, final exam be damned. But she noticed as she turned a little, Ron was still shaking and jerking around. "Scabbers," he hissed, nearly knocking off the Invisibility Cloak.

He clutched his hand over the pocket where Scabbers was still wriggling, trying desperately to get free. "What are you doing?" he shouted, coming to a halt. "You stupid rat! Ow!" He jerked back, and held up his hand to them, shrugging off the cloak.

"Ron!"

"He bit me!" Ron said, eyes wide as he stared at his hand. "Scabbers bit me!"

They had to go, Calla knew. But something wasn't just stopping Ron, but stopping her. It was wrong. She could feel it in the air, the unmistakeable beginnnings of something awful. It felt like electricity, like hot static. It was making her restless, as well as worried.

"Ron, be quiet!" Hermione hissed over to him, as he sill struggled to keep his hold on Scabbers. "Fudge'll be out here soon, we have to go!"

"He - won't - stay - put!"

Calla watched Ron's wrestling with the rat, and she knew there was something very, very wrong. He'd never been this way, not even with Crookshanks. He was plainly terrified, but of what? There were an awful lot of things for a rat to be scared of, she supposed, but to this extent? And he should be safe in Ron's pocket, too. Yet he was writhing with every muscle in his body, trying to get out of Ron's grip.

"What's the matter with him?" Ron asked desperately, turning to Calla with very wide eyes. All she could do was shake her head.

"Let's go!" Harry was saying, but no one was listening to him.

Something twisted in Calla's stomach, and the uncomfortable rash of foreboding crept over Calla's arms, over her shoulders, up the back of her neck. "This is all wrong," she muttered. "Something's wrong, I can feel. I've - I've seen things.

"Seen things?" Hermione said dubiously, but Calla went on, mind racing.

"It's a full moon." Her breath caught. No, no, no. "We have to get back. Now!"

No one ran after her, but even as she tried, something ginger streaked out to block her path, tripping her over. "No, Crookshanks," Hermione moaned, as Calla steadied herself. "Go away, Crookshanks. Go away!"

But the cat didn't listen. "Crookshanks," Calla hissed. He just came closer, yellow eyes fixed on the wriggling lump Ron was holding.

It was too late. Scabbers shot out from Ron's grasp and he yelled, flinging the cloak off for good and pelting after him with a roar. "Ron!" Calla shouted, but he kept running.

The other three exchanged nervous glances, and then took off after him. They couldn't run with the cloak, though; it streamed behind them and Calla cursed quietly, running as fast as she could over the hard ground. Her heart was pounding so loud, but she could hear the heavy thunder of Ron's feet as well as the patter of Crookshanks' paws as she ran. "Ron, come back!" she hissed, but he didn't, and she wasn't exactly surprised.

"Get away from him - get away - Scabbers - come here, Scabbers!"

There was a loud thud and a yell and Calla ran faster, desperate to stop whatever was happening, or about to happen. "Keep moving!" Harry said as they ran on.

"Gotcha!" Ron yelled happily, and Calla breathed a sigh of relief, slowing a little bit. "Hurry up!" Calla exchanges a confused look with Hermione, and sped up again, coming over a little mound to see Ron sprawled on the ground, shoving Crookshanks off him with Scabbers quivering in his pocket. He clamped his freed hands tightly over the lump, shaking and white. "Scabbers," he was saying. "Scabbers!"

"Ron, come on," Hermione said, panting . "Come on, back under the cloak! Dumbledore and the Minister, they'll be coming out soon!"

"We need to go," said Calla, shivering. "Ron, come on, please."

She was panting, but looked around. They'd left the cloak behind, too; they'd have to run back for it, and quickly, before it was discovered by someone else. But before she could say this, before she could even catch her breath, there was a soft thudding of paws on the ground. She turned, following Ron's shaking gaze, and her eyes landed on that same massive, pale-eyed, black dog.

"You're back," she whispered, staring at it. "Harry, don't you recognise-"

"From Magnolia Crescent." Harry's voice was hoarse.

"That's a Grim," Ron said shakily. "Calla, that is a Grim."

She took a step towards the dog nervously. The bracelet was still in her pocket; she took it out, holding it to the dog as she bent her knees slightly, so she could look at its eyes properly. "Hello," she said.

"Calla, get back!" Harry hissed.

"I know what I'm doing," she said.

"No you don't!"

She ignored him, and uncurled her palm so the dog could see the bracelet. "Did you leave this for me?" The dog's nose brushed the tips of her fingers. "What are you? Have you come to warn us? Is there something here?" The dog only looked at her. "Someone? Is - is Sirius Black here?"

The dog tensed up. "He is? Where?"

She stood up sharply, turning to the others. "We have to go. Now. I've got to get the cloak."

She went to run for it but as she did so, the dog sprang past her, tail brushing against her as she moved out of its way just in time. The bracelet slipped through her fingers as Ron shouted, "Scabbers!" and she took off down the hill, eyes peeled for that silvery fabric. She spotted it on a mound by a large boulder and grabbed it, clutching the material tightly to her chest. People were coming out of the hut. They'd have to hurry.

She sprinted back to the others, and had to hold back a scream at the sight of the dog pinning Harry to the ground. "Get off!" she called to it, voice shaking. "Leave him alone!"

The dog rolled off and Calla rushed to Harry, still with a tight grasp on the cloak. She pulled him to his feet with clammy hands, just as the dog rounded on Ron, snarling and spitting. "Leave him," she hissed to the dog. "What are you doing?"

But the dog didn't listen. Everything seemed to happen at once, as Hermione collided with Calla as she tried to pull them under the cloak, as they hurried towards Ron, as the dog sank its teeth into Ron's forearm and he howled in pain. "No!"

The dog was pulling Ron across the ground, and he shook from the rough journey. "Let him go!" Calla told the dog, but it didn't listen. It had gone, it seemed, absolutely feral.

And what had Remus said? What had she not listened to? Stay away from big black dogs. Here was one dragging Ron - and, she realised with a start and a jolt back to memories of her visions, Scabbers the rat - away from them.

Calla, Harry and Hermione all broke into a chase after them, Ron flailing in the dog's grip. "Harry! Hermione, Calla! Run! Go!"

They just ran towards him faster, but they were too far away, and he and the dog slipped down a whole in the ground, disappearing from sight. "Come on!" Calla yelled back to Harry, still running, not keeping an eye on the sky.

Something rammed into her stomach and threw her backwards to slam on the hard ground, teeth rattling. She breathed heavily, winded, and passed the cloak to her other hand, pulling out her wand, not that she thought it was going to do much good. It didn't feel right. None of this felt right. But she remembered - the dog and wolf and rat and stag and crows. Everything was coming together.

"Calla?" Harry's voice asked, his footsteps thudding closer. His glasses were askew on his face. "Calla, are you alright?"

She nodded dazedly, stumbling to her feet. "What on Earth?"

Her eyes fell on the dark shape before them that cut across the starlight. "The Whomping Willow."

"Help!" shouted Ron's voice, buried somewhere in the distance. "Help!"

"Ron!" Harry yelled, rushing forward again. Calla lunged after him, pulling him just out of the way of a thick tree branch. "Ron!"

"Wait," she said, as the branches swung madly. "Hermione?"

"I'm here!" Hermione called, hurrying on towards them, ducking under a violent branch. "I'm here!"

"Harry," Calla said, as the others fumbled for their wands. "Don't you see what tree this is?"

"Lumos," Harry whispered, lighting up the space in front of them just as another branch came roaring towards them. "That's not good."

They all ducked, scrambling back. "We have to get to Ron," Calla said, glaring at the tree. Ron's foot was hooked into one of the roots, but she knew it wouldn't stay like that for long; especially if the dog pulled too hard and broke a bone. "Hermione, what spells do you know?"

"I - I don't-" She looked like she was wracking her brain, trying to think as she pointed her wand up. "Petrificus totalus!"

Nothing happened; if anything, the tree got angrier at that, and knocked her flying off her feet. "Ron!" Harry called. "Ron, we're trying, hold on!"

"Immobulus!" Calla yelled up at the tree. Absolutely nothing happened. "Come on," she muttered, tears springin too easily to her eyes. "Let us get to our friend." She and Hermione said it together this time. "Immobulus!"

But still nothing happened. The tree slapped Calla across the face and she went flying, hearing the shatter of her glasses. She had to squeeze her eyes shut, taking them off. "Watch!" she shouted. "My glasses have broken, There's glass on the ground, I don't know where!" She braved opening her eyes. There was nothing in them that she could feel, but something had caught on her cheek - whether the slap or a piece of glass - and it stung badly. Someone hurried over to her.

"Calla? Can you see?"

"No!" she replied, clutching her glasses. "Hermione!"

Hermione sprinted over, and knelt awkwardly at her side. "Don't touch the ground," Calla said, as Hermione raised her wand.

"Hold your glasses out to me," she instructed, and Calla did so with a shaking hand. "Oculus reparo!"

There was a snapping sound as the lenses fitted back together and she gingerly put them back on, the world coming back into focus. The Whomping Willow was still thrashing, and Ron's foot had disappeared from view. "We have to run," she said, grabbing Harry's hand and then Hermione's. "Come on, we might not have long."

"How will we get in?" Hermione cried, stumbling.

"I don't know," she admitted. "But the dog did. And - and Remus says he used to be able to get in when he was in school. So there must be a way."

"If we time it right," Harry said, Seeker's eyes trained on the tree. "We might be able to..."

They waited. Hermione danced anxiously on the spot and Calla breathed heavily, hands tight around the cloak and her wand. She had to hope that they'd help, that it would work, that they could save Ron.

"Move!" Harry yelled, and they sprinted forwards together, making a dash for the roots where the hole in the ground was. A branch thumped down just behind them and Calla let out a shrill shriek, stumbling forward. She stopped just in time before she crashed into another branch, swinging the other direction, and pulled her friends back. They took another two steps and the tree thrashed again, knocking Hermione off her feet; her hand slipped away.

"Hermione!" Calla yelled.

She stumbled to her feet, looking surprised but okay. "I'm fine," she said. "Come on!"

They scrambled towards the roots but as they did so, another branch swung right for them. Harry and Hermione ducked and Calla tried to move, but felt it slam into the side of her head. She was sent sprawling to the ground, wand flying; it fell down the hole. "Come on!" she shrieked, crawling forward. Everything felt heavy, but she swung her legs around and slipped down, catching ahold of her wand. "Harry!" she shouted up. "Hermione!"

There was a yell from above. She shivered, stomach feeling like a rock had fallen into it. "Harry?"

"Hang on!" she heard Hermione's muffled voice call. She shrieked, and there was a very loud thud. "We'll be with you in a minute!"

"What's going on up there?" Calla yelled. "Hermione!"

She stepped back from the opening, shaking. If they were hurt... She glanced back down the long tunnel that lay ahead. "Ron!" she shouted down it, but there was no reply. "Ron, we're coming! Just - just hold on!"

There was a loud yell, and someone crashed through the opening. Calla was pushed forward, slamming onto the ground as Harry stumbled blearily to his feet. "Are you okay?" she asked quickly, and he nodded, with a knuckle-white grip on his wand. "Where's Hermione?"

"She's just-"

Hermione flew through the openin to the hole, crashing into Harry. "Sorry," she muttered, getting hastily to her feet. "Are you- Crookshanks!"

Her cat had darted forward from behind Calla and scampered up the hole, placing his front paws on a little nob by the base of the trunk. Calla stared. "Has that always been there?"

"How did he know?"

"He's friends with that dog," Harry said. "I saw him with it."

"Me too," Calla said. "A few months ago, he led me out to a window, with Matilda, and the dog was there. And so was Moony. Owl Moony." She blinked. Both her kitten and her owl seemed to have taken to the dog, and she'd never felt anything sinister about it... So why had it attacked wrong? It didn't feel right, or normal. Something was wrong. It was totally off.

"Come on," Harry said grimly. "And keep your wands out. Calla, you - you have got-"

"It's here," she said, tightening her grip on both her wand and the Invisibility Cloak. "Let's go."

They followed Crookshanks, which Calla thought may have turned out to have been a terrible idea, but he was their only form of direction now. His tail flicked the air as they crept down a low, earthy slope and emerged into a very long, dark passage.

"This is creepy," Calla muttered. She supposed it was suitable, considering it surely led to the Shrieking Shack.

"Where's Ron?" Hermione asked in a very nervous whisper.

"This way," Harry said, leading them on by the light of his wand.

"Calla," Hermione said lowly, "where does this passage lead?"

"Hogsmeade," she said. "The Shrieking Shack."

Hermione let out a rather unHermione-like whimper. "Wonderful."

They went on as quickly as they could, backs bent in the low ceilinged passageway. Crookshanks' tail bobbed every now and then, and the passage seemed to go on forever. It had to lead to the Shack, Calla thought. It was certainly long enough, and creepy enough. She thought of Ron; was he already in the Shrieking Shack, being mauled to death by a recently feral dog? Was he hurt, was it already too late? It couldn't be, she had to tell herself. They'd have to arrive in time to save him.

The tunnel began to rise, and Calla stooped even lower, running as best as she could in the hunched position. Then it twisted, and they followed Crookshanks' tail as it whipped around the corner. At the end of this part of the tunnel, there was a light ahead. It was very dim, but it was certainly there. Relief flooded her, but it was short lived as she hurried onwards. "Ron?"

They had to get there and they had to get there now. Calla would calm the dog down, she had to, and they'd get Ron to safety and figure everything else out on the way. It'd all be alright, she promised herself. It didn't feel very true.

They approached the entrance with caution and caught their breaths. Calla looked at Harry worriedly, heart hammering, but she knew they had to go on. They pressed through the end of the tunnel, coming out into a large, dim, dusty room. Definitely the Shrieking Shack.

But there was no Ron, and no dog. Something pressed at the edges of Calla's mind, a memory of the fire. Omens. She squeezed her eyes shut. The changing face, dog to man. Her stomach squirmed. Could it be? No. Surely not.

"Calla?" Hermione's said quietly. "I think you're right. I think this is the Shrieking Shack."

She opened her eyes, being sure to take everything in. If they had to make a quick exit, she'd need to know any other way out. There was a single window, boarded up, but perhaps it could be broken with a lot of force and a very strong spell. But nothing else that could let them out, except a door on one wall that led to a shadowy hallway.

Her eyes fell on a dilapidated chair with chunks torn out of it, half rotted. This was where Remus had had to come every full moon when he was her age, all alone and bound, tearing at himself and destroying everything else. Tears sprang to her eyes and she huddled closer to Harry. He looked at her and she knew he was thinking of the same things.

There was a creaking sound coming from above them. Calla glanced up, frowning. How did a dog, carrying a whole human body, make it up the stairs? She suddenly felt very much like running for help, but she still knew she couldn't leave Ron, or Harry and Hermione. "Be careful," she whispered, as they advanced further into the room. "That's not a normal dog."

McGonagall could transform into a cat, she knew. They'd learnt about animagi, but surely someone would know if - if Sirius Black was one. Surely Remus would know. She couldn't think that, but she had to. Was that why he had warned them? But why not say why? If Black was the dog... He had had that bracelet. He'd given it to her, to what? Taunt her? Lure her into a forest and to her death? It had been stalking them all year, not the Grim, but a very different and very real bringer of death. One that had killed her parents.

"Sirius Black might be up there," she whispered, and both Harry and Hermione stared at her. The changing face in the fire. It all dawned on her with a sickening weight. She was right, she knew it. This was why it all felt wrong. "Keep a hand tightly on your wand."

As quietly as they could, they crept out into the hall and up the crumbling, dilapidated staircase. They had to move very slowly indeed to ensure they didn't make any noises or creaks that would alert the dog - or rather, as Calla thought was becoming increasingly likely, Sirius Black - to their presences.

Everything but the floor was covered in a very thick layer of dust, but there was a thick white strip that showed something had been dragged along it. Ron. Calla felt sick again. At least there wasn't any blood.

The thought of it kept running over and over in her mind, Ron dying, Ron bleeding out in pain. Mauled to death, or blown apart as Sirius Black had done to all those muggles? It felt like forever before they reached the landing. "Nox," they all whispered, extinguishing the wandlight.

Calla squinted down the hallway; there was only one door open, and she was sure that was where Ron had been dragged into. As the three of them crept quietly towards it, she could hear a very faint sort of moaning sound, and then a loud purr. For a fleeting second, Calla hoped it was Matilda, but knew that wouldn't be her luck. At least Ron was still alive, she thought. They could still save him. If one of them could take him back to the school and the others hold Sirius Black off long enough to send reinforcements... It was unlikely. She rather thought they all ought to take Ron and make a run for it.

Calla leaned forward, peering through the tiny sliver between the door and the frame, and then Harry kicked it in.

There was a magnificent four poster bed in the middle of the room, where Crookshanks lay purring. Ron lay pale on the floor beside it, leg sticking out at an odd - broken, most likely - angle. "Ron," Calla whispered, hurrying forward. The only injury she could see was his leg, which was a good sign at least. "Should we move him onto the bed, or just take him?"

"Where's the dog?" Harry asked, looking around in confusion. Hermione held Ron's arm tightly.

"Not a dog," he muttered, gritting his teeth. Calla's stomach plummeted. She'd been right.

"We need to get out of here," she said. "Now."

"It's a set up," Ron said, then hissed in pain as Calla tried to get him upright. "Calla, it's a trap. He's a dog."

"Sirius Black," Calla whispered, feeling all the blood drain from her face. "An - an animagus?"

Ron nodded, wincing in pain. "Harry," she said. "Run."

"What are you-"

"Harry, go."

The door slammed shut. Calla wheeled around, staring at the shadows where a man stood with a gaunt face and matted black hair and hollow eyes. He could have been a corpse. Perhaps he would have been less dangerous if he was, but he wasn't. "You," she whispered. She was right. She hated it. "You!"

Her stomach twisted as everything fell into place. He reached out a hand to her, clutching a wand - Ron's wand, she realised dimly. It was withered and the nails were broken. The dying hand.

"Expelliarmus."

Calla tried to get a grip on her wand, but it was no use. It flew out of her hand and into Sirius Black's, and the Invisibility Cloak fluttered to the floor. It occurred to her then that no one knew where they were. No one would hear them even if they screamed for help, a feat which Calla didn't honestly think her lungs were up to achieving. But her mind went to her godfather; he had the map. Maybe, possibly, through some miracle he'd see. But the Shack wasn't even on the map, she realised, hiding her groan.

Sirius Black stepped closer and Calla stumbled back, slipping onto the edge of the bed. "I thought you would come for your friend," Black said, advancing even further. His voice was hoarse, cracked, like he'd forgotten how to use it. How long had he been in his dog form. "Your father would have done the same."

Calla wanted to spit at him to not talk about their father, but no words would come to her. She shuddered hollowly.

Black looked awfully relaxed about everything, worryingly so. He hadn't, however, cast any spells yet, or made much of a move to truly hurt them, save for what he'd done to Ron. He just held the wands in his hand, staring at them.

"It's brave of you," he said. "Harry, Calla. Not to run for a teacher."

"How do you know we haven't told anyone?" Calla said boldly, though her voice felt like withering in her throat. Black looked at her, considering, and tilted his chin. "You know Remus Lupin. I know you do. He's teaching here, at Hogwarts. He's my godfather, he's told us everything. He's - he's coming," she told him and hoped she sounded convincing even though her voice faded on her words. "And you'll be really, really sorry."

"I'm sure I would be," Black said. "If Remus really was."

Calla shrank back then, shuddering. She didn't have anything else she thought she could say. "So what then?" Harry said. "You've come to kill us, have you? Like you killed them!"

"Your father jumped to conclusions, too," Black said quietly.

"Don't talk about him," Harry said. "You've no right."

Something flickered on Sirius Black's waxy face, something almost human. Calla clutched at the bedsheets nervously, trying to calm her heart which felt like it had leapt into her throat and was battling to escape through her mouth. If she tried to speak she was sure she would be sick.

Before her, Harry was clearly shaking with anger. His hands twitched, likely for his wand, and Calla squeezed her eyes shut, trying to comb her mind for something, anything that might help. A portent of the future, a way out. A way to help Ron and if they could, to take down Black. She felt something at the edge of her thoughts, something oddly comforting, but at the sound of a yell she snapped her eyes open. Harry had lunged forward, and Hermione reached out to grab him, pulling him back. Calla grabbed his hand, and he pulled her up to standing.

"If you want to kill them," Ron said, voice shaking as he got clumsily to his feet, very pale, "you'll have to kill us first." He tried to push past Calla, swaying on his leg, but she held him back, trying to get him to lie down before he hurt himself.

To her surprise and horror, Sirius Black echoed her thoughts. "Lie down," he told Ron. "You will only damage that leg more."

Calla stared at him. What did he care? He was a murderer, for goodness' sake. Her stomach twisted uncomfortably. "Lie down, Ron," she murmured quietly, eyes on Black.

"Calla?"

She took a very nervous step forward, and immediately felt like her legs were going to give out. Black was staring at her.

"Give me my wand back," she said quietly. He didn't oblige, not that she expected him to.

"Did you hear me?" Ron shouted from behind her. "I said you'll have to kill us first, too!"

"There need only be one murder tonight," he said, and the way he looked at her didn't look like he wanted to kill her. She didn't want to die, but she didn't understand.

"Why's that?" Harry asked, moving forward to stand beside Calla. "Didn't care last time, did you? Didn't mind killing all those Muggles to get at Pettigrew! What's wrong? Gone soft in Azkaban?"

"Don't taunt him," Calla hissed, shoving him back. She turned her eyes to Sirius Black. "You gave me a bracelet, that day by the forest. My mother's. Why? Why give it to me? Taunting me, were you? Trying to get at me, get into my head?" Her voice was shrill, she knew, and Black was just staring at her. "Why not just kill me? You had to give that to me first! What did you do? Go into the house, take it from the wreckage? Some sick kind of trophy now your - your Lord was gone?"

"Calla," Black said sternly.

"Don't call me by my name," she spat. "You're sick."

"Don't you know I knew your parents?"

"YOU KILLED THEM!" Harry bellowed, surging forward again. "I DON'T CARE IF YOU KNEW THEM, YOU KILLED THEM!" He went running forwards as if to attack Black and Calla first tried to stop him, but couldn't reach him before his fist slammed into the side of Black's face.

The wandtips turned away from Harry as he forced Black towards the wall, shaking the dust from the ceiling. Calla lunged forward, trying to grab the wands even as they sparked, missing her by mere inches. She grabbed Harry just as Black's fist closed around his throat and she shrieked, slamming her hand into his face. He turned, smacking into the wall, but he kept his grip. "No," he was saying, voice hoarse. "I have waited too long."

"Don't you dare," Calla spat at him, trying to pull Harry back. She clasped her fingers around Black's, trying to prise them off of Harry's throat. But he was a lot stronger than her, and she felt angry tears burn in her eyes as she tried. "I won't let you."

Hermione swung a leg out to catch Black's ankles and he stumbled away, loosening his hold. Calla grabbed Harry, pulling him back as the wands clattered to the ground.

They both lunged, but Calla cried out as something sank its claws into her arm. She stumbled back, trying to throw Crookshanks off of her, and ended up hitting Black with the very angry cat. He lunged for her and she shrieked, scraping her nails against his face, which was just inches from her. Years of fending off Dudley and other Muggle playground bullies had taught her how to use her nails when she couldn't use her fists, and Black howled as he stumbled away from her.

Crookshanks sank his claws further into her arm. "I thought you liked me!" she shrieked at him, shoving him off finally. He went scampering towards Harry and the wands, and Harry kicked at him just in time. The cat went flying back, hissing, but then something else sprinted into the room, another cat.

"Matilda?" Calla shrieked, as her own kitten joined the fray. "Matilda, no you don't!"

But Matilda wasn't going to hurt her. She scampered over to Calla, standing by her legs and batting her tail, meowing loudly and turning quickly between Calla and Black. "Matilda, get out of here!" she cried. "You'll get hurt!"

"Get out of the way!" Harry's voice yelled, as he picked up his wand and whirled around to face Black. Matilda scraped lightly at Calla's ankle and sprinted back, to scamper over Harry's feet. Calla rushes to his side as Ron and Hermione fell back, dishevelled and - in Ron's case - very green in the face, onto the four poster bed. Calla grabbed her own wand, though her arm was aching from where Crookshanks had sank his claws in.

"Calla, get behind me," Harry said.

"No," she said shakily, aiming her wand at Black. "No, this is down to both of us."

"You're hurt."

"I'll live," she said, though if she was honest, she wasn't entirely sure of that. "He killed our parents." The words had such a weight to them that she was sure she'd now never be able to shake them. Her hands were trembling around her wand. She wanted dearly to try and see something, to search her mind for a future where they all lived, but she hardly dared to blink.

"Going to kill me, are you?" Black laughed hollowly, from where he had sank to the bottom of the wall. Calla was almost proud to note the bloodied wells that her nails had made on his cheeks.

Harry stepped closer, wand aimed at Black's heart, and Calla followed, face set firmly. "You killed our parents," Harry said, but his wand arm was shaking. She wasn't sure she could do it, and she didn't think Harry could either, not really. But if it came to him or them... They'd have to.

"I don't deny it," Black said hoarsely. "If you knew..."

"You sold them out to Voldemort," said Harry. "You're the reason they're dead! That's all we need to know." He jabbed his wand closer to Black's heart and Calla shuddered. "You never heard her, did you? Our mum. Pleading with him, for her life and for ours. Trying to stop Voldemort from killing us... And you did it."

"You're the reason he found us," Calla said tremulously. "You're the reason our parents are dead, you're the reason Remus has been alone for so long. You didn't just destroy our family, you destroyed his too." She tightened her grip on her wand and pointed it firmer at Sirius Black, praying that it did not waver.

But before either Calla or Harry could say another word, something ginger streaked past them, easing onto Black's lap. The next second, Matilda had settled herself decisively over Calla's feet. "Get off," Sirius Black said to Crookshanks, trying to push him gently off of his lap. Gently. There was something almost fond in his voice.

But Crookshanks sank his claws into Sirius' arm and wouldn't let go. If they wanted to hurt Black, they'd have to hurt Crookshanks too, and no matter her confusion Calla would not kill a cat. She heard Hermione sob, and that settled it. She stood for a moment not knowing what to do at all, and her hand shook as she found herself lowering her wand.

"I don't understand," she said quietly. "Remus doesn't understand. Why... Why you would do it."

Black just looked at her, face gaunt and haunted. Her wand hung by her side as she considered him, waiting for something to be said, anything. Harry's wand was still raised, aimed right at Black's heart. She didn't know how long it would take, until he would shoot a spell and knock him dead.

There were footsteps on the stairs. They were like a breath in the room, and Calla sank back, turning. "We're up here!" she yelled. "We're up here! It's Sirius Black!"

Black startled in a jerking movement that almost had Crookshanks falling off of him. Harry inched forward and Calla fell back, stumbling towards the door. "Help!" she as Hermione both screamed, as footsteps thudded along the hallway, and the door burst open in a shower of bright red sparks.

"Remus!" She let out the biggest sigh of relief in her life, sinking back against the wall. "Sirius - Sirius Black - Harry - he's - he's going to kill-"

Remus stormed in, face white and bloodless. His eyes flickered to Calla, then to Ron lying on the floor, then a cowering Hermione and then to Harry, who still had his wand point over Sirius Black's heart.

"Expelliarmus!" he said, and all the wands in the room leapt to him. Calla turned, startled.

"Remus, what are you doing?"

He didn't answer her, as he moved further into the room to stand nearer Black. He stared at him, at Crookshanks in his lap, and his mouth fell open. "Remus?"

He spoke then, but not to her. His voice shook with emotion. "Where is he, Sirius?"

Calla stared at him. Where was who? She stared between him and Sirius Black, wondering what she'd missed. She didn't understand this, not at all. Black's face was blank, entirely expressionless. For a moment it was as though he was entirely frozen. Then he raised a shaking arm, pointing his finger at something in the room. No. At Ron.

"What?" she found herself whispering. Ron blinked at Black, looking entirely bewildered, just as Calla felt.

"But then..." Remus said, staring intently at Black. "...Why hasn't he shown himself before now? Unless-" His eyes widened suddenly. "Unless you two switched, at the last minute. Without telling me. Unless he was the one..."

Black's gaze never left Remus, but slowly, he nodded. "I don't understand," Calla whispered.

Her words died in her throat. The next thing she knew, Remus had lowered his wand, and had strode over to Black, pulled him to his feet so that Crookshanks went scrambling away, and had embraced him like a brother. All Calla could do was stare.

"I DON'T BELIEVE IT!" Hermione screamed, and Calla faltered, just staring.

"What have you done to him?" she asked, voice quivering, gaze turned harshly on Sirius. "What's going on?"

"He hasn't done anything," Remus said gently. "I didn't understand until now, but if you'll let me explain-"

"I've been covering for you!" Hermione shrieked. "All year! And you've been his friend! How long have you been plotting for this?"

"We haven't been plotting anything," said Remus, very calmly. Calla knew he was telling the truth, knew somehow that Remus had reason to trust Sirius Black again even if she didn't understand it, and that meant Sirius Black didn't mean them harm. Maybe he never had. Maybe he hadn't been the one...

"Hermione," she said, glancing at her friend, who was white with anger. "It-"

"He's been helping him get into the castle!" Hermione said shrilly. Ron had gone quite white and looked like he might faint.

"No he's not!" Harry shouted back. "Why would he?"

"Harry, Calla, I'm so sorry, you can't trust him!"

"Why not?" Harry roared back, face contorted with confused anger.

"Because - because," Hermione faltered. "Because he's a werewolf."

A stunned silence fell over the room. Calla stared at her, hardly believing that Hermione had figured it out, or that she thought that made him in league with Black. "Of course he is," she said, staring at Hermione, who faltered. Clearly what she'd thought had fallen apart a little. "And he's my godfather, Hermione."

Remus had gone very white, as had Ron. "I'm afraid you're not entirely right, Hermione," he said, his voice remarkably calm. "I am a werewolf, you are correct. But I certainly do not wish Calla or Harry any harm, nor have I been helping Sirius."

"But you're his friend! We just saw-"

"I have not been his friend for twelve years," Remus said. "Not until tonight." He glanced at Black, who was looking gaunt, and then to Harry and Calla, who were both still slightly stunned from Hermione's accusation. "You both understand this, Don't you?"

"Of course," Calla said quickly, rushing over to him. "I - I know."

"Yeah," Harry said. "You - you... I still don't understand what... Just happened, but I know you wouldn't hurt us." A smile of relief flickered across Remus' face. "Hermione," Harry said. "Remus wouldn't hurt us."

She was very pale, Calla noticed, and shaking a little as she sat on the bed. "How long have you known, Hermione?" Remus asked tensely, with tremendous effort.

"Ages," she said hollowly. "Since Snape set that essay. And I thought - I thought..."

"That I meant to do Calla and Harry harm, because of it? That they didn't know, from all their years of knowing me, that the reason they couldn't stay with me was because I transformed into a monster every full moon?"

"I - I don't-"

"Snape set that essay in the hopes that someone would figure it out, and try to get me sacked." Calla clenched her fists. "It seems you did manage to figure it out, Hermione, though quite how you reached your other conclusions I don't entirely understand."

"You... Because Halloween, y-you weren't at the feast. And, and because I wondered why would he break out now and logically it was because he knew that there was someone here who would help him! I overheard Fudge saying, in the Three Broomsticks, that he - that Black kept saying in his cell, that he was at Hogwarts, someone was at Hogwarts. I thought - I thought he meant you!" Remus sighed. Calla just stared at Hermione, shocked and still reeling. She could tell that her brother was the same. "And then - and then you came here, how did you know?"

"The map," Harry said, the same time it dawned on Calla.

"Yes, Harry," Remus said. "I had it out on my desk earlier this evening, and saw the four of you leave the castle to go to Hagrid's hut. Even under the cloak, the map can see you." Hermione clutched at a bedpost. "Twenty minutes later, you left Hagrid, and set off towards the castle. But this time you had someone else with you."

"Who?" Calla asked, quite confused even as something pricked her memory. The only new addition had been... Scabbers. No. But the rat... And Ron... And Crookshanks. "No."

"Yes," Remus croaked, pacing. "I didn't understand at first, I thought it impossible. How could he be with you? How could he be alive?"

"But no one was with us!"

"And then I saw another dot, moving fast towards you, labelled as Sirius Black. I saw him collide with you, then take two of you into the Whomping Willow."

"But there was only one of us!" Ron insisted, quite confused.

"No, Ron," said Remus. "Two of you."

He paused in front of him and the little lump still in his pocket, and Calla knew. "Scabbers?"

"What?" Ron asked, looking at her like she was quite mad. "What's Scabbers got to do with anything?"

"Do you think I could have a look at him?" Remus asked mildly.

"What? No! What's wrong with Scabbers?"

"Rather a few things," Remus said. "It's important."

Calla and Harry exchanged glances and though Harry still looked rather lost, they both nodded at Ron. Nervously, and still very confused, he lifted Scabbers - who was still writhing - out of his pocket by his tail. Wormtail. It clicked in Calla's. Of course. Moony, Wormtail, Padfoot and... And Prongs. Calla's dad.

But that meant...

Remus leaned closer to Scabbers, who was now thrashing desperately. "What?" Ron said, holding Scabbers close to him. "What's Scabbers got to do with anything? He's just my rat?"

"That's not a rat," croaked Sirius Black suddenly.

"What do you mean?" Ron looked up, and Calla shook her head, the blood drained from her face. The name was in her throat but she hardly dared to speak it. "Of course he's a rat!"

"No, he's not," said Remus quietly. "He's a wizard."

"An animagus," said Sirius, hoarsely. "By the name of Peter Pettigrew."