"Expelliarmus!" Sirius Black croaked, pointing Ron's wand at them.

Our wands shot out of our hands, high in the air, and Black caught them. Then took a step closer. His eyes were fixed on Harry.

"I thought you'd come and help your friend," he said hoarsely. His voice sounded as though he had long since lost the habit of using it. "Your father would have done the same for me. Brave of you, not to run for a teacher. I'm grateful...it will make everything much easier..."

Harry with rage filling his face started forward but Hermione, Ron and I quickly grabbed him and held him back. "No, Harry!" Hermione gasped in a petrified whisper; Ron, however, spoke to Black.

"If you want to kill Harry, you'll have to kill us too!" he said fiercely, though the effort of standing upright was draining him of still more color, and he swayed slightly as he spoke.

Something flickered in Black's shadowed eyes.

"Lie down," he said quietly to Ron almost like a caring father would say, which I found weird. "You damage that leg even more."

"Did you hear me?" Ron said weakly, though he was clinging to Harry to stay upright. "You'll have to kill all four of us!"

"There'll be only one murder here tonight," Black said and his grin widened.

"Why's that," Harry spat, trying to wrench himself free from our grip. "Didn't care last time, did you? Didn't mind slaughtering all those Muggles to get at Pettigrew...What's the matter, gone soft in Azkaban?"

"Harry!" I warned. "Stop it!

"HE KILLED MY MUM AND DAD!" Harry roared, and with a huge effort he broke free of our grip and lunged forward-

Perhaps it was the shock of Harry doing so stupid but Black didn't raise the wands in time-one of Harry's hands fastened over his wasted wrist, forcing the wand tips away; the knuckles of Harry's other hand collided with the side of Black's head and they fell, backward, into the wall-

Hermione and I screamed; Ron was yelling; there was a blinding flash as the wands in Black's hand sent a jet of sparks into the air that missed my arm by an inch. Uncovering my eyes I noticed Black's hand had found Harry's throat-

"No," he hissed, "I've waited too long-"

The fingers tightened, Harry choked, his glasses askew.

I got up off the ground and ran tackling Black off of Harry. Hermione came kicking Black; Ron had thrown himself on Black's wand hand. I punched Sirius in the nose.

"Get out of the way!" Harry shouted at us.

We didn't need telling twice. I get off Sirius quickly and stand behind Harry. Hermione, gasping for breath, her lip bleeding once more, scrambled aside, snatching mine, hers, and Ron's wands. Ron crawled to the four-poster and collapsed onto it, panting, his white face now tinged with green, both hands clutching his broken leg.

Black was sprawled at the bottom of the wall. His thin chest rose and fell rapidly as he watched Harry walking slowly nearer, his wand pointing straight at Black's heart.

"Going to kill me, Harry?" he whispered.

"Harry stopped right above him. A livid bruise was rising around Black's left eye and his nose was bleeding.

"You killed my parents," Harry said, his voice shaking slightly. but his wand hand quite steady.

Black stared up at him out of those sunken eyes.

"I don't deny it," he said very quietly. "But if you knew the whole story."

"The whole story?" Harry repeated a furious pounding in his ears. "You sold them to Voldemort. That's all I need to know."

"You've got to listen to me," Black said, and there was a note of urgency in his voice now. "You'll regret it if you don't...you don't understand..."

"I understand a lot better than you think," Harry said, and his voice shook more than ever. "You never heard her, did you? My mum...trying to stop Voldemort killing me...and you did that...you did it..."

Before either of them could say another word, something ginger streaking past Harry; Crookshanks leapt onto Black's chest and settled himself there, right over Black's heart. Black blinked and looked down at the cat.

"Get off," he muttered, trying push Crookshanks off him.

But Crookshanks sank his claws into Black's robes and wouldn't shift. He turned his ugly, squashed face to Harry and looked at him with those great yellow eyes. To his right, Hermione gave a dry sob.

Harry stared down at Black and Crookshanks. I couldn't see his face but I could tell he was fighting with himself.

Harry raised the wand but still stood frozen. I don't think he could do it.

And then came a new sound-

Muffled footsteps were echoing through the floor-someone was moving downstairs.

"WE'RE UP HERE!" Hermione screamed suddenly. "WE'RE UP HERE-SIRIUS BLACK-QUICK!"

Black made a startled movement that almost dislodged Crookshanks as footsteps were thundering up the stairs.

The door of the room burst open in a shower of red sparks and I wheeled around as Professor Lupin came hurtling into the room, his face bloodless, his wand raised and ready. His eyes flickered over Ron, lying on the floor, Hermione, cowering next to the door, to me, face washed over with relief, to Harry, standing there with his wand covering Black, and then to Black himself, crumpled and bleeding at Harry's feet.

"Expelliarmus!" Lupin shouted.

Harry's wand flew once more out of his hand; so did the two Hermione was holding. Lupin caught them all deftly, then moved into the room, staring at Black, who still had Crookshanks lying protectively across his chest.

Then Lupin spoke, in a very tense voice.

"Where is he, Sirius?"

I looked quickly at Lupin confused. I didn't understand what Lupin meant. Who was he talking about? I turned to look at Black again.

Black's face was quite expressionless. For a few seconds, he didn't move at all. Then, very slowly, he raised his empty hand pointed straight at Ron. Mystified, I glanced around at Ron, who looked bewildered.

"But, then...," Lupin muttered, staring at Black so intently it seemed he was trying to read his mind, "...why hasn't he shown himself before now? Unless"-Lupin's eyes suddenly widened, as though he was seeing something beyond Black, something none of us could see, "-unless he was the one...unless you switched...without telling?"

Very slowly, his sunken gaze never leaving Lupin's face, Black nodded.

"Professor," I interrupted loudly, "what's going on-?"

But I never finished my question, because what I saw made my voice die in my throat. Lupin was lowering his wand, gazing fixedly at Black. The Professor walked to Black's side, seized his hand, pulled him to his feet so that Crookshanks fell to the floor, and embraced Black like a brother.

I felt as though my stomach had fallen out.

"I DON'T BELIEVE IT!" Hermione screamed.

Lupin let go of Black and turned to her. She had raised herself off the floor and was pointing at Lupin, wild-eyed. "You-you-"

"Hermione-"

"-you and him!"

"I didn't tell anyone!" Hermione shrieked. "I've been covering up for you-"

"Hermione, listen to me, please!" Lupin shouted. "I can explain-"

I could feel myself shaking, not with fear, but with a fresh wave of fury. I had trusted this man.

"I trusted you," Harry shouted at Lupin, who took the word right of my mouth. "And all this you've been his friend!"

"You're wrong," Lupin said. "I haven't been Sirius's friend, but I am now-Let me explain..."

"NO!" Hermione screamed. "Harry, don't trust him, he's been helping Black get into the castle, he wants you dead too-he's a werewolf!"

There was a ringing silence. Everyone's eyes were on Lupin, who looked remarkably calm, though rather pale.

"Not at all up to your usual standard, Hermione," he said. "Only one out three, I'm afraid. I have not been helping Sirius get into the castle and I certainly don't want Harry dead..." An odd shiver passed his face. "But I won't deny that I am a werewolf."

Ron made valiant effort to get up again but fell back with a whimper of pain. Lupin made toward him, looking concerned, but Ron gasped.

"Get away from me, werewolf!"

Lupin stopped dead. Then, with an obvious effort, he turned to Hermione and said, "How long have you known?"

"Ages," Hermione whispered. "Since I did Professor Snape's essay..."

"He'll be delighted," Lupin said cooly. "He assigned that essay hoping someone would realize what my symptoms meant...Did you check the lunar chart and realize that I was always ill at the full moon? Or did you realize that the boggart changed into the moon when it saw me?"

"Both," Hermione said quietly.

Lupin forced a laugh.

"You're the cleverest witch of your age I've ever met, Hermione."

"I'm not," Hermione whispered. "If I'd been a bit cleverer, I'd have told everyone what you are!"

"But they already know," Lupin said. "At least, the staff do."

"Dumbledore hired you when he knew you were a werewolf?" Ron gasped. "Is he mad?"

"Some of the staff thought so," Lupin said. "He had to work very hard to convince certain teachers that I'm trustworthy."

The room fell silent and Lupin looks toward me.

"Nia, you haven't said a word," he said. "It is because-"

"I could care less if you were a vampire, let alone a werewolf," I said frowning but it quickly turned into a serious look. "What pisses me off is that you've been helping him all this time" I pointed at Black, who suddenly crossed to the four-poster bed and sank onto it, his face hidden in one shaking hand. Crookshanks leapt up beside him and stepped onto his lap, purring. Ron edged away from both of them, dragging his leg.

"I have not been helping Sirius," Lupin said. "If you'll give me a chance, I'll explain. Look-"

He separated mine, Harry's, Ron's and Hermione's wands and threw each to its owner; I had caught mine, stunned.

"There," Lupin said, sticking his own wand back into his belt. "You're armed, we're not. Now, will you listen?"

I wasn't sure what to think. Was this a trick? But for some reason, I had a feeling it wasn't.

"If you haven't been helping him," Harry said, with a furious glance at Black, "how did you know he was here?"

"The map," Lupin said. "The Marauder's Map. I was in my office examining it-"

"You know how it works?" Harry said suspiciously.

"Of course I know how to work it," Lupin said, waving his hand impatiently. "I've helped write it. I'm Moony-that was my friends' nickname for me at school."

"You wrote-?"

"The more important thing is, I was watching it carefully this evening, because I had no idea that you, Nia, Ron and Hermione might try and sneak out of the castle to visit Hagrid before his hippogriff was executed. And I was right, wasn't I?"

He had started to pace up and down, looking at us. Little patches of dust rose at his feet.

"Nia wasn't with you so I don't know how she got out undetected," Lupin said. "But the three of you, you might have been wearing your father's old cloak, Harry-"

"How d'you know about the cloak?"

"The number of times I saw James disappearing under it...," Lupin said, waving an impatient hand again. "The point is, even if you're wearing Invisibility Cloak, you still show up on the Marauder's Map. I watched you cross the grounds and enter Hagrid's hut. Twenty minutes later, the four of you left Hagrid, and set off back toward the castle. But you were now accompanied by somebody else."

"What?" Harry said. "No, weren't!"

I couldn't believe my eyes," Lupin said, still pacing, and ignoring Harry's interruption. "I thought the map must be malfunctioning. How could he be with you?"

"No one was with!" Harry exclaimed.

"And then I saw another dor moving fast toward you, labeled Sirius Black...I saw him collide with you; I watched as he pulled two of you into the Whomping Willow-"

One of us!" Ron said angrily.

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

He had stopped his pacing, his eyes moving over Ron.

"Do you think I could have a look at the rat?" he asked evenly.

"What?" Ron said. "What's Scabbers got to do with it?"

"Everything," Lupin said. "Could I see him, please?"

Ron hesitated, then put a hand inside his robes. Scabbers emerged, thrashing desperately; Ron had to seize his long blad tail to stop him escaping. Crookshanks stood up on Black's leg and made a soft hissing noise.

Lupin moved closer to Ron. He seemed to be holding his breath as he gazed intently at Scabbers.

"What?" Ron said again, holding Scabbers close to him, looking scared. "What's my rat got to do with anything?"

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

"What d'you mean-of curse he's a rat-"

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

"An Animagus," Black said, "by the name of Peter Pettigrew."