A/N: AU Third year - what could have happened if Sirius had found one moment of reason while trying to reach Pettigrew at Hogwarts?

There are some quotes from Prisoner of Azkaban scattered through the text - just tiny snippets - I leave it to you readers to find and recognise them -))

The Difference a Letter Makes

1. The Letter

The forest seemed to be going on forever. Thick undergrowth spread through most of it, only interrupted by narrow paths trampled down by the strange and mysterious creatures which roamed among the trees. Unusual cries and noises could be heard in the night, while it was almost bereft of sounds during the day. Only birds seemed to make themselves heard when the sun was out. But in spite of the many magical and even dangerous beasts living in the forest it seemed peaceful on the morning of a crisp fall day, which promised to become a sunny day in the most wonderful colours that nature produces in autumn.

The silence at the edge of the forest was disturbed by the sound of the panting of a huge black dog whose paws drummed against the grassy ground. The dog halted, lifted his nose in the air, sniffed and let out a short bark. Had anyone been around to hear it, they would have noticed that the bark sounded happy and relieved. The dog continued and now entered the forest for good, trotted ahead in a more confident manner. It never stopped its sniffling, in the air, on the ground, and it looked around warily, as if to see whether it was being followed. Deeper and deeper it penetrated a forest that none of the people living in its vicinity would even dare to invade.

Not that there were that many people living on the edge of that forest. Only a couple of farms had withstood time there and only a handful of inhabitants of those farms were holding on. They were convinced that the whole forest was cursed. No one knew of anyone who had ever really been inside of the vast wooded area. It seemed like it was forbidden. But some of the farmers or members of their families had glimpsed the strangest kinds of creatures from its edges, and most told tales about wolves howling in the nights of the full moon, though no one had ever seen them. Why, it wasn't even 15 years since these howls had ceased. Old Mr McGregor still looked for the man who must have finally shot that wolf. He hadn't been too concerned though, as there was not one single sheep he had ever lost to it. Still, it was easier without the threat of having rabid wolves in the area.

The dog did not seem to have a care or a fear to invade that seemingly impenetrable forest. Once it had determined there was no one near it trotted on, sniffing its way along.

It was a strange dog. Massive, but appallingly thin. The fur was thick, the hairs quite long and matted. It was dirty. The tail was feathered with long tresses of fine black hair, equally matted. The ears flopped and bopped up and down in rhythm with the trot.

While the size of the dog was surprising, as it was even bigger than an Irish Wolfhound, the most startling property of the creature were its eyes. They were of a sparkling light blue, very pale, sometimes almost stormy grey. They were intelligent, alert eyes. Something was odd about this dog, it seemed to be very cunning, knowing exactly how to avoid people who could see it.

The dog had good reason to stay out of the way of anyone, Muggle or wizard. It was not a dog after all, it was the infamous escaped convict Sirius Black, on the run from recapture. He was on his way to Hogwarts, the school of witchcraft and wizardry, having only one single thought in his head: catch the traitor Peter Pettigrew, who had framed him after committing the crime for which Sirius had been imprisoned in Azkaban, the dreaded wizarding gaol, guarded by soul sucking Dementors. Only one other small thought was in Sirius' mind, to protect his godson Harry Potter from Pettigrew.

For Peter Pettigrew was an Animagus, too, a wizard who could transform into a rat. No one but Sirius knew he was still alive. Sirius, himself an Animagus and currently in his alter form of the black dog, had seen the proof of what he had always suspected, when the minister of magic, Cornelius Fudge, had left him a copy of the Daily Prophet, the wizarding newspaper, back in July, during one of his regular inspections of the prison. Sirius still had the photo from the front page, which showed a wizarding family. One of the children had the rat on his shoulder. The rat, which Sirius recognized immediately. It was all the incentive he needed to regain strength. Enough to slip out of his cell, through the corridors and finally out of the fortress. He had managed to swim to the shore, not too difficult a task for the dog as the island wasn't too far away from the shore. Then he had travelled south to get a glimpse of his godson.

And finally, having accomplished that, he had turned northwards again, travelled in a steady lope to gain safety in the Forbidden Forest. He needed to be close to Hogwarts, inside the grounds, where there would be no Dementors. Sirius was certain that the headmaster of Hogwarts, Albus Dumbledore, would never allow a Dementor access to the grounds of the school.

And so he sighed with relief, when he caught the familiar scent of the Forbidden Forest. It was known terrain, had he not spent countless nights of the full moon here with his friends, back in his school days, when they were still all together? How the loss of James and Lily Potter still hurt him. And even more he felt the loss of Remus Lupin, his best friend and lover, even though Remus was still alive, wherever he was.

Remus had been the reason why Sirius, Peter and James had become Animagi. He was a werewolf and after having found out his secret, the three boys had been determined to find a way to help Remus cope with the terrible transformations during the full moon nights. And they had found the way, became Animagi, became animals. As animals they were able to join him on his full moon nights, helped him to remain much more calm and prevented him from harming himself as he had done before.

'All because of the dratted rat!' Sirius thought, 'but just you wait, I'll get you soon enough!'

By nightfall he had reached the centre of the forest. He looked for a place to sleep. There was a stream nearby and he decided to go in and take a bath, first in his dog form, then again, as a human. He cleaned himself as well as he could. His robes, still the coarse grey tattered prison robes, were beyond repair.

But Sirius had a goal. The four friends had stored a secret stash somewhere quite close by on the night before they had left Hogwarts. They had decided to dig in their first wands and some other memories from school, and if this stash was still in place Sirius would have something different to wear and more important, he'd have a wand again. A means to survive the coming winter in the forest. He finished the bath in the cold water and shivered when he got out.

His human form was an even more frightening sight than his dog form. Skeletal was the body, almost dead were the eyes, matted and tangled the hair that reached his elbows. His teeth were yellow and he had a long beard. Over all he looked like he had not been taking care of himself for a decade or longer. Not losing as much as a thought about all that though, he pulled the old robes over his head and transformed back into the dog.

He still hadn't eaten, and so he sniffed around until he was able to catch a squirrel. It was devoured as it was, right there. Then Sirius drank some water from the stream and finally he looked around for a tree whose roots would make for a good bed. Once he had found one he lowered himself into the hollow space and curled up in a tight ball. Sleep came, and with it came the nightmares. They were bearable only in his dog form. He had attempted to sleep as a human twice and both times he had given up and transformed, before he was able to go back to sleep.

When the next morning dawned, he was up again. He moved on, quickly, knowing where he was going. He walked for most of the day, then he found the place he was looking for. He sniffed around carefully before he approached it. The spot was beyond the Shrieking Shack, the derelict looking house which had served as a cage where Remus had spent his full moon nights in his school days. The stash had been buried in a clearing not far away from the shack, but it was fairly close to Hogsmeade, where Sirius expected Dementors to be. He could get there in dog form and he could dig in dog form, so when he had found the spot, he didn't lose time, he started digging right away and found what he had been looking for. It was a good sized box, completely untouched. No one had been here before him. And apart from Remus and Peter no one alive knew about this. Sirius looked and sniffed around, but no Dementor was close by, so he transformed and grabbed the box out of the hole. Night was falling and he got back into the forest unseen. Relief washed over him again. So far, everything had worked out fine. He would hide the remaining three wands again, just taking out his own.

Once he was well away from the edge of the forest, and far enough away from Hagrid, the game keeper's cabin, Sirius sat down and opened the box. His hands were trembling. This box bore so many memories which started to come back to him now. It was painful to look at its contents. There was his own first wand, ebony, with a dragon heartstring. He picked it out of the box and immediately a warmth bubbled up in his hand, the spark of the re-bonding with his wand.

'It still fits me,' he thought delightedly and waved the wand.

Like the first time he had held it in his hand in Ollivander's shop, the wand spat out sparks and red stars. Sirius smiled and said:

"Lumos!"

The wand lighted up and there was another wave of relief going through Sirius. He let himself flop to the ground, laughing giddily and feeling happy for the first time in more than twelve years. His magic was still there within him. He hadn't lost the ability to use a wand like most of the other prisoners in Azkaban who had felt the Dementors much worse than Sirius. Still, he had worried, whether the Animagus transformation was maybe the only magical ability he had left.

Then he ventured deeper into the box. There were their school robes. Each of the four had put one of the robes inside the box. There were four letters – short letters, they all wrote back then with a short memory of their school days and what their friendship meant to them. Sirius didn't read them. He looked down further, found a knife and an empty roll of parchment and several other things which had been significant to them.

Sirius decided to hide the box again. If he needed anything he could always come back, but for now it was enough to take his old robe out and see whether it still fitted him. It was too wide, but almost long enough. It felt warm and comfortable and soft. Sirius pointed his wand at the coarse prison robes, which were rough and didn't protect from the cold at all, in spite of the thick fabric. He burned them in seconds. The black robes were all he had now. He'd have to spend most of his time in dog form anyway and Padfoot didn't freeze easily. Not outside of Azkaban in any case. What was most important was that he had a wand again. There were hardly any words to describe his happiness about that fact. He could do magic again, he felt like a wizard again.

Sirius used this ability to hide the box. He then started by transfiguring several pebbles into things he needed, like a blanket and even boots. Then he started to explore his closer surroundings.

During the next few nights he moved around Hogwarts in dog form. All the while he saw the moon waxing and thought of Remus. And then one evening, about five days before the full moon at the end of October, Sirius saw someone coming out of the castle, who looked like he was going for a longer walk. It was close to dusk, and he couldn't see who it was. He didn't expect to know the man anyway. So Sirius hid in the thick undergrowth at the edge of the forest. The man came closer, passed the Whomping Willow on the way and stood still, contemplating the tree. Sirius watched him, mesmerized and finally he knew why, when he caught a whiff of the man's scent.

His eyes weren't too good as a dog, but his nose was fine just like a dog's. And the scent wafting over to him now was a scent he would have even recognised in his human form: Remus.

'Remus! What's he doing here? Oh Merlin, if I could only run to him now. If only he'd listen to me, I might get his help. Remus, my love…'

It took all his determination not to leave his cover straight away. But then reason came through. He couldn't stay this close. If he had caught Remus' scent, then Remus must be able to smell him as well, his nose was as fine as the dog's and it even worked in his human form. Sirius drew back immediately. He slowly retreated into the forest, crawled and finally turned around to find his hiding spot.

He sat down to think about the new situation. If Remus was there he might go and check the secret stash. He'd know immediately that Sirius had already been there. What was there to do? Then he remembered the parchment in the box. He transformed, opened the box and took it out. Transfiguring something into a quill and some water into ink was one thing. Then he started to write.


Remus Lupin was back home. That's at least what he had felt at the first moment he stepped up the familiar stairs to the main entrance of Hogwarts. He was back to teach Defence against the Dark Arts at the urge of Headmaster Dumbledore. To ensure the safety of the children, he would be supplied regularly with the Wolfsbane potion, a potion his father had developed during long years of research. The potion helped him to keep his own mind during the transformations. It meant he would be free to transform in his chambers as he was a harmless wolf once the transformation was completed.

But Remus had not thought of the memories. After the first few days they started to haunt him. He turned around a corner and expected to hear James calling after Lily. He walked up a staircase and saw Peter running down to get to a class in time. And he passed some nooks and corners and remembered Sirius and he kissing and cuddling there. It became so painful that he spent all his time going straight from classes to meals and from there to his chambers.

The teachers' quarters were mostly on the ground floor. There was a corridor leading from the Entrance Hall to the area where the teachers spent their free time and had their chambers. The teacher's lounge was there, too, with access to an orchard and a fairly large garden, hidden from the students by a thick, impenetrable hedge. This was the only area Remus was free from the memories as they had never managed to get even close to it as students.

When he felt like he was in a cage he went for walks. He thought everything over and over again, it wouldn't let him rest. Ever since the day Sirius had been torn from him, he had been confused. His heart told him, that Sirius could never have done it. His reason though had always contemplated the facts he knew to be facts. But whenever he thought about those facts, all he really knew was that Sirius had been found on the spot, laughing like a maniac, his wand in his hand. And he tried to remember the trial until he remembered that there had been no trial. The hearing then? Not much of that either, and he had not been allowed to attend. That had practically been between Bartemius Crouch, the head of the Department of Magical Law Enforcement and Sirius alone. And then Sirius was shipped off to Azkaban. The reasoning of the ministry officials made sense. And yet there had always been that little bit of doubt remaining in Remus' head and heart. In the first two years of Sirius' imprisonment he had tried numerous times to get a visitor's permit to see him and talk to him. He had believed, that if he could hear it all from Sirius, he could figure out the true story. It had been denied, either on the grounds that he was a werewolf and thus a Dark Creature or that he had been known to be Sirius Black's lover and therefore he was a suspect himself. After two years he had given up. He surmised that Sirius was by now as good as mad and would probably not be in a state to even be coherent anymore.

But he had never stopped loving Sirius. It had been terrible to live without him. First of all there was a slight physical pain from being away from his bonded mate. Then there were the transformations, horrible again, as they had been before the pack had met and stopped Moony from doing harm to himself. Numerous times he had been visited by Poppy Pomfrey who would not leave Remus even in his darkest days. She was one of his very few anchors in that stormy ocean that his life had become. And numerous times had she found Remus almost torn to pieces after his transformations. Edward Lupin, Remus' father, had been able to heal the smaller wounds, but when Remus was found too injured he had always called on Poppy. In all her years of caring for Remus after his transformations at school she had learned to love the young man like one of her own sons. While Remus hated her to 'fuss', he secretly enjoyed being cuddled and she had never made it a secret that she was not the least bit afraid because he was a werewolf. There was never even so much as a flinch in the mediwitch's reaction to him. One reason why he loved her back just like a second mother.

Now he was in her care again. Just six years ago Edward had brought the potion to completion, it was highly complex, but Severus Snape, the school's potions master, was well capable of brewing it. There was still something left to do for Poppy, as the transformations themselves remained quite painful and took a lot out of Remus.

The next full moon was near. It would be on the night after Halloween. Remus had five doses of the awful brew left to swallow. The wolf was high in his blood, in spite of his potion and he couldn't stand the closed rooms. He went out for a walk, idly choosing his way without giving much care of where he went. He thought about his teaching, how much he loved the students and how they seemed to thoroughly like him, too. He had already recognized the Weasley twins as images of himself and his friends at school and while they amused him greatly, he had been able to make it clear, that his class was a no-nonsense zone for them. They had accepted his teaching in trade though and he quickly noticed, that many of their antics were born out of boredom or unsatisfying teaching styles. He knew they were very good at potions, even though Snape didn't give them the marks they deserved. And he soon noticed they were excelling in his classes as well. So one day after about two or three weeks he had kept them back after class and had arranged an agreement between them. They would not disrupt his classes and he didn't keep his eyes out for their antics outside of his classes. Which the twins had accepted with a huge grin on their faces.

To Remus' surprise he found himself in front of the Whomping Willow. He stood frozen and closed his eyes. A flood of memories washed over him, as the tree started to get in gear and Remus quickly jumped out of the reach of the angry twigs and branches. He thought about going to the shack. But then he shook his head and turned. He walked in the direction of Hagrid's cabin instead, now with the idea to look how Hagrid did after his disastrous first class. While he continued on his path he sniffed the air. Was there a slight memory of Sirius' scent? Remus looked around. He knew the Headmaster thought Sirius would be coming to Hogwarts, but he couldn't be there, could he? Not with the Dementors around, it would be impossible for Sirius to cross their lines and they were positioned all around the gates.

Remus knocked on Hagrid's door. He heard Fang, the boarhound bark as Hagrid came to the door and opened it.

"Oh, it's you! Good evening, Remus, come on in!"

"Hi Hagrid. I thought I wanted to see how you were doing after your ordeal with your first class."

"Quite okay, Remus, thank ye. Sit down, please. Want some tea?"

"That would be lovely, thank you."

Remus took a seat at the table. Once they had a steaming mug of tea in front of them, he looked up and asked Hagrid:

"Hagrid, what do you think, could Sirius be on the grounds?"

"Haven't seen anything that would indicate it, Remus. – Why?"

"Just because…"

He took a sip of the tea. Then he asked in a low voice:

"Do you think he really did it? You've seen him just before he took flight and Peter went after him, did you think he looked like he could have done it?"

Hagrid stared at him.

"What makes ye say somethin' like this, lad? He was caught on the spot, wasn't he?"

"Yes, but do we really know what happened? I mean none of the Aurors who arrived there saw what happened, they only found Sirius, and Sirius must have been almost out of his mind."

"True. – Well, he seemed out of his mind of grief, when he got there. I had already gone through the house an' had found the bodies of James an' Lily. He argued with me abou' 'arry. Asked me t' give him the boy. But I had me orders from Dumbledore an' he wouldn't act agains' 'em. Gave me the bike instead. Said, he wouldn't need it anymore."

"Hm. He loved that bike. He must have known something already, something that would either kill him or put him into Azkaban. If only I could find out what really happened."

"D'you think they'll catch 'im again?" Hagrid asked.

"I don't know. I should think so, yes…"

When Remus returned to the castle half an hour later he was trying to push all thoughts of Sirius out of his mind. He went to bed and even found sleep.


For several nights Sirius looked for a way to get his letter to Remus. He could only hope Remus would be convinced by the contents and do as he had begged him. It was difficult to sniff out where he would find Remus and how to get there. He had hidden in some shrubs on the school grounds when students were out and had learned that Remus was teaching Defence against the Dark Arts. He had to smile about that and wondered whether the students knew about Remus being a werewolf, but supposed they were not told. He wondered in what house Harry was and had his reply to this question when the first Quidditch match of the year took place and Sirius was able to sneak onto the stands to watch Gryffindor play against Hufflepuff. And even though the light was dim and the weather was awful, he could see Harry playing as the seeker. The familiar red Quidditch robes he had worn himself when he was on the team were a dead give-away. Sirius' heart filled with love and pride to see Harry fly for his own house. Whenever he caught a glimpse of his godson he was baffled again at how much Harry looked like James. He wondered whether anyone had told Harry about Sirius being his godfather. 'Probably not,' he thought. Then he wondered, if Harry knew about Remus having been a friend of his parents, but dismissed that thought as well. Remus liked to remain very private and he would not have told Harry for fear of causing the boy sorrow.

Sirius saw how the match went lost. To his distraught he had to witness his godson falling from the broom and dropping fifty feet down to the ground. He was relieved when he noticed that Albus had slowed down the fall and that they brought Harry back up to the castle, seemingly alive. Then he saw the broom being destroyed by the Whomping Willow.

'Oh dear! That one's lost for good,' he thought, while hiding out from the Dementors who had swarmed the area and had caused Harry to fall. Sirius was sure it had been their fault. He had seen Harry look down and lose conscience. 'What did they make you relive, Harry?' Sirius asked himself. He could only imagine that it must have been something horrible, since it affected him so badly.

Sirius still hadn't been able to find a way to give Remus his letter. He had watched the moon and decided to wait until after the full moon. He also watched for any sign of Remus coming to the Shrieking Shack, but he did not turn up. Sirius wondered, if he locked himself up inside of the castle now. He could hardly bear the thought of his Remus in a cage.

Then, four days after the full moon, Sirius ventured into the castle for the first time. He waited until well after midnight, then sniffed his way around. He knew the secret passages better than anyone and didn't need to pass through the main entrance to get inside. His first idea was to look for the teacher's quarters, but they hadn't been able to get in there as students, so he didn't expect to get in there now. Then he thought to find Remus' classroom. He sniffed all the trails he could find of Remus and the strongest scents he followed. They led him to his destination soon enough and Sirius found the door to the classroom open. He knew there was another door which would lead him into the office and expected it to be locked. He tried several unlocking spells, the third of which worked. He entered the office quickly and closed the door behind him. Then he turned on the candles to get some light. He looked through the office and smiled. It had the typical Remus feel, and when Sirius looked around he could see several things Remus already had when they had been together. There was a pile of homework parchments on the desk. Sirius didn't touch a thing, but he decided to put his letter just under the top parchment. He read the name on it: Hermione Granger, Gryffindor, Third Year. Werewolves! 'Hm. She must be one of Harry's classmates. Neat handwriting. Looks like she's good at what she does… would Remus really treat the subject of werewolves with his students?'

Sirius didn't linger. He left the office, looked around and locked it as it had been, then went to the classroom door and opened it a tiny bit, peered out and, when no one seemed to be around, went out into the hall and closed the door. He transformed immediately and crept back out of the castle. He made for the forest as fast as he could and hid again. He had made himself some sort of a hiding spot up in a tree, where he could be as warm as was possible. He knew he had just put his fate into the hands of his old lover. He could only wait for the outcome.


Remus got up quite easily the first time after the full moon. He had returned to classes the day before. Now he went to breakfast and felt quite well again. Poppy met him at the breakfast table and looked him over. He smiled.

"I'm fine again, Poppy, no need to fuss about me."

"I'm just giving you a quick check. You do look fine to me though, Remus."

Remus was early and classes would only start an hour later, but he thought to make up for lost time and grade some of the essays he still had to work through. He'd promised Hermione to grade her werewolf essay, even though she would not have had to finish it. But he would reward her for all her work. He sat down at his desk, picked up the essay from the pile and was taken aback when he saw a piece of parchment that lay right underneath Hermione's essay. He put the essay back on the pile, taking the letter instead and started to read it. The familiar script made his heart pound.

"Moony

Peter Pettigrew is alive and in the castle! He is in his rat form and he's a pet of one of the Weasley boys. Is there a way you can get hold of the rat, take it to Dumbledore and make it show himself? Does the potions master have some truth serum maybe? Ask him about the secret keeper and where he went after Halloween 1981! And then contact me, please.

I implore you, Remus, help me! I didn't do it, I wasn't the spy. And I still love you."

In place of a signature there was nothing but the print of a big paw. Attached to the letter was the photo of the Weasleys and there, on Ron's shoulder, sat Scabbers, the rat. Remus almost fainted. So his doubts had been right! He wanted to believe Sirius desperately. He looked up at the clock on the wall. There was still enough time to show the letter to Albus Dumbledore. He went back to the Great Hall to see if the Headmaster was still there.

Dumbledore was just getting up and coming out. Remus stopped him and asked him quietly:

"Albus, would you have a moment of time for me, please?"

"Of course, Remus, what is it?" the kind old Headmaster asked back.

"Can we go to your office?"

"Naturally. Come along, dear boy."

They went to the Headmaster's office and sat down. Without another word, Remus took the letter and the newspaper clip out of his pocket and passed them to Dumbledore. Dumbledore read the letter, saw the clip and demanded:

"This asks for some explanations, I'd think. Why does Sirius say Peter Pettigrew is a rat?"

Remus sighed. Then he plunged into a quick explanation:

"I don't want to miss class time, Albus, so I make it very short, but I'll answer any question you might have when we have more time. James, Sirius and Peter had become Animagi in their fifth year. They did it to be able to join me on full moon nights. Do you remember when I stopped having bad wounds, only having the odd scratch anymore after my transformations? I would expect Poppy to have told you something of her observations. When they were with me I would not hurt myself, the wolf was playful, but calm most of the time."

"They were quite foolish, but I'd say the end justified the means, you had some amazing friends there, Remus."

"Yes, Albus, they were. The best. But we couldn't tell anyone, none of them ever registered. I suspect that's how Sirius got out of Azkaban. But, Albus, if what he says here is true, then I don't even want to think about the hell he's gone through!"

"Neither do I. This looks like Ron Weasley. Do you know whether he has a rat with him here?"

"No, but I can always ask him to stay back after class and then make him get the rat. If it's really Peter I can only hope he doesn't suspect anything yet. Without him there's no way we can prove Sirius's innocence."

"And you know how to force an Animagus to show himself?"

"Yes, we learned it in case one of them would have trouble transforming back."

"Very good. When do you have the Gryffindor third years for the next time?"

"This afternoon coincidentally."

"Good. Please ask Mr Weasley to take you to his dormitory and procure that rat. We will have to go from there. We'll ask Severus to come up with some Veritaserum and if he stays with us through the questioning, I would expect him to see the truth, too. He would be a very reliable witness, especially since you've been rather enemies."

"I agree with you. I'll do as you say."

When the afternoon class came to an end, Remus took a deep breath and asked Ron:

"Ron, can you stay behind after class, please? I have a favour to ask of you."

"Yes, Professor."

Ron walked up to the teacher's desk and Remus noticed that Harry and Hermione stayed behind, too. Remus turned to Ron and asked:

"Ron, is it true, that you have a pet rat?"

"Yes, Scabbers. – Why?"

"We have reason to believe something's wrong with this rat, do you think I could have a look at it?"

"He's up in my dormitory, but I can get him. He's not feeling too well right now."

"Do you mind if I accompany you up there so you can get it for me?"

"No, that's okay."

Remus went up to Gryffindor tower with the students. Harry and Hermione stayed close to Ron through it all. Remus was amused at how they were anxious, but then he soothed their worries:

"You are not in trouble at all, but I'll have to ask you to come with me to the Headmaster with the rat, Ron. – And no, I'm afraid you two can't come along. You'll be informed once the investigation will be over."

Remus went with Ron all the way to the dormitory. Ron took Scabbers out of his bed and showed him to Remus. The rat started to tremble immediately.

"I'm sorry to do this, Ron, but I'll have to freeze him. – Petrificus Totalus!"

"Why did you do this, Professor? What's wrong with Scabbers?"

"You have to come with me, Ron, I think we will owe you a thorough explanation of this whole thing. He's your pet after all."

"To the Headmaster?"

"Yes. Come along, please. We won't hurt him, I promise."

Once they had arrived at Dumbledore's office, they settled down on some chairs, while Dumbledore called Snape through the fireplace. He asked him to bring a vial of Veritaserum along. Only minutes later, Severus came out of the fireplace and looked around. He saw Ron and frowned.

"Severus, please take a seat. Now, Remus, can you please do what you have to do to that rat?"

"You said you won't hurt him, Professor!" Ron exclaimed.

"I won't. If this rat is really a rat it will not do him any harm, but if it's what I think it is, then you'll see what comes out of it. And then we'll explain, okay?"

"Okay."

Ron handed Remus the petrified rat. Remus forced it to transform. Ron watched with the same wide eyes as Severus how the rat turned into a small man with little hair and watery eyes.

"Pettigrew!" Snape spat.

He started to have an idea, why they wanted Veritaserum to be administered.

"Indeed, Peter Pettigrew," Albus remarked.

Remus had continued to mutter another spell, then bound Pettigrew with ropes.

"Okay, I have put a hold Animagus spell over him, he cannot transform back until this spell is lifted. – Hello, Peter…"

"Remus! Headmaster! Severus!"

Peter Pettigrew squeaked. Ron was sitting in front of him and stared. Slowly he turned to Remus and asked:

"Is that the Peter Pettigrew who is supposedly dead after Sirius Black killed him and Harry's parents?"

"Spot on, Ron!" confirmed Remus.

Severus stood up and went to Pettigrew. He lifted his left arm as well as he could through the ropes and pushed back the sleeve of a very worn set of robes. He dropped the hand in disgust. Albus asked:

"Does he have the mark?"

Severus only nodded. He handed the vial to Albus and looked over Pettigrew, appalled. Remus looked at Severus questioningly. Severus only pushed back the sleeve on his own left arm and showed him his Dark Mark. Ron's eyes widened even more. This surely meant that Snape himself had been a Death Eater.

"Severus had returned to our side as a spy about a year before Voldemort fell, Remus. It takes one to see one."

"Well done, Severus," was all, Remus could say before turning to Peter.

"Now I'd like to know from you who was James' and Lily's secret keeper, Peter?"

"How should I know? Sirius was to be their secret keeper."

"You wouldn't know why Sirius would explicitly tell us to ask you this question?" Remus inquired.

Ron admired his calm demeanour.

"Why should I? He's been the spy as you all know! Wouldn't you do better to go after him, now that he's out of Azkaban?"

"Don't try to fool me, Peter, you know that's not possible. You know I can SMELL your emotions, and I smell fear! I can smell you're lying, Peter! And you have the Dark Mark."

"But he tried to kill me and now he's out to kill Harry and me!"

"He may have tried to kill you, Peter, but don't you want to tell us the truth without forcing us to give you the truth serum? I hear it's not very pleasant to take, is it, Severus?"

"No, it's not," Snape confirmed.

He watched with quite an amount of amusement, how Lupin took his old friend apart.

"I am telling the truth, Remus, I knew all along he'd not forget me, not even in Azkaban. He'll be after you next, I'm sure."

"Oh, you are? Well, there's one thing I'd like to have you explain, Peter, just a little detail, really. If he had cast the curse that killed all those Muggles around you, how many were there again? Ten? Twelve? Never mind how many, well, how do you think he could have achieved killing the Muggles and not kill you as well? You were, as I remember, right amidst them… how do you explain the finger the Aurors found? The finger that's missing from your right hand there!"

Pettigrew remained silent. Dumbledore picked up the vial, conjured a small goblet of water and added three drops inside. Remus and Severus helped him administer the contents and then they waited for a few minutes for the serum to start working. Ron watched and listened to the following questioning with baited breath. He would have some interesting news for Harry soon, he knew that.

"Back to the task at hand. Peter, who was the Potter's secret keeper?" Dumbledore asked.

"I was."

Dumbledore, Remus and Severus stared. Then looked at each other. Then Dumbledore asked:

"So what happened after the Fidelius charm was cast?"

"A few days after the spell was cast, I was summoned to the Master. The Dark Lord was most pleased when I told him that everything was in place and he could get to the Potters. He went, but never returned. I had to hide immediately, but Sirius found me in London the very next afternoon and wanted to kill me. I thought of a diversion and shouted at him how he could have betrayed James and Lily, then cut off my finger, caused the gas explosion, which killed the Muggles and transformed at the same moment."

The three others looked at each other and finally, Dumbledore asked further questions:

"What did you do after that explosion?"

"I lived among the rats for a few weeks, until the worst was over, then found a wizarding family where I could live safely. I kept an eye on the Daily Prophet. There were still enough of the Dark Lord's followers out there, I was afraid they would kill me for being the one who sent the Dark Lord to the Potters."

Dumbledore turned to Remus and Severus.

"That can only mean one thing: Sirius Black is innocent. He has been sent to Azkaban for a crime he had not committed. We have to find him, Remus, before the Dementors find him."

Remus nodded. He turned to Ron:

"Ron, you can return to your house. Please only speak about this to Hermione and Harry! We will call you up for explanations once all of this is through, so do not under any circumstances tell anyone else about it. It could cost an innocent man his life if you are not careful. I would even suggest to only talk to your friends away from anyone else. Okay?"

"Okay, Professor. May I go now?"

"You may go," said Dumbledore.