So, I finally stopped stalling and decided the exact direction this story is going to take. I'm actually very excited about this. Please ignore plot holes and focus on my wonderful creativity ;)

Also, I'm going to try and post updates as to the progress of this fic on my profile.

The entrance to Dumbledore's office was the same as ever, except the password was currently, 'mint humbug'. It was unclear to Aziraphale and Crowley exactly how often Dumbledore changed his password, and both were of the opinion that it was most likely just on a whim. Crowley could have sworn the Gargoyle rolled its eyes, hearing yet another strange password. The reaction to most of what Dumbledore did was either an eyeroll or awed silence, or both. Probably.

They didn't speak as the spiral staircase carried them up to the office. They had already discussed Professor Trelawny enough and decided it might be a good idea to talk to Harry about it, because according to McGonagall he had looked tense and worried during her lesson with him that day. Aziraphale had wanted to talk to Professor Trelawny, but Crowley had assured him it was futile. Telling her that her prophecy had frightened most of the third year Divination class would probably encourage her.

Approaching the door to the office, they heard the familiar sounds of the portraits chatting together, Dumbledore's calm, quiet voice included in the discussion. The door swung open as they approached, revealing the office behind. It too, had not changed, the spindly instruments still perched on tables and cabinets around the office, the headmaster's desk in the centre of the hub of spinning, ticking and humming objects.

Dumbledore smiled and stood politely as they entered, but behind the usual twinkle in his eyes, Aziraphale sensed a gravity. This was an interview with a distinct purpose. They seated themselves in front of the headmaster's desk. The portraits fell quickly silent, watching the meeting closely. Another sign that something important was to be discussed.

"Welcome back," Dumbledore said, as they all settled around the desk, "and how, may I ask, has the first day been so far? I do rather miss the days when I was more involved in the happy hubbub of first day mayhem."

"We have been to see the Hippogriffs," Aziraphale explained, before telling Dumbledore about Trelawny.

He sighed. "Professor Trelawny, believe it or not, has actually made many accurate predictions in her life. However, due to her rather…dramatic personality, people have the tendency to disbelieve her. Such is the way with many in her branch of magic."

Both Aziraphale and Crowley nodded, remembering Cassandra from their days in the Trojan war.

"But I asked you here to discuss something more…close to home than the misty musings of the future," Dumbledore continued.

"Sirius Black," Crowley said, and received a nod of affirmation.

"I think it is important for you both to know the connection that Black has with Harry Potter," Dumbledore said, his face grim. Crowley had the feeling it wasn't a pleasant connection.

"Lily and James Potter knew that Voldemort was after them, during the war," Dumbledore began, "I, therefore, suggested that they go into hiding. Using a Charm known as the Fidelius Charm, a little-known piece of magic which prevents anyone find the people under the charm when they are within a certain place. The Potters hid in their cottage in Godric's Hollow. And that was where Sirius Black came in. He was the Potters' secret keeper, James' best friend. Only he could break the fidelius charm on them and betray their location."

Fidelius. Fidelis, Aziraphale thought, faithful, loyal, trustworthy. Like many magical terms, and indeed English words, the charm had a Latin root. The Potter's had had to trust someone to keep their location a secret from Voldemort. They had chosen Sirius Black and Aziraphale had the feeling that Sirius Black had not been very fidelis.

"Black betrayed them," Dumbledore concluded.

"And now he's after Harry," Crowley looked grave.

They sat in silence which seemed to be happening a lot. Crowley wondered if this was what the Christian prophets had felt like, getting some new revelation every few days.

"But now, the task which I need you to perform for me," Dumbledore looked at them sharply, "And I would not ask this unless I trusted you greatly. I need you to track down Sirius Black. But" he added, for once seeming as though he couldn't find the right words, "I need him…questioned. Because" and now Dumbledore looked almost uncomfortable, "I have reason to believe he may be…innocent."

"Innocent?" Aziraphale did not understand. Dumbledore had just told them that Sirius Black had betrayed Harry and his family to the Dark Lord. He was also guilty of killing twelve muggles. And now he was innocent?

"I cannot be sure," Dumbledore said quickly, "but I believe it would be prudent to find out. Sirius Black could prove useful, if Voldemort returns. Which, as you can see, is starting to seem more likely."

"Useful?" Aziraphale was still having trouble understanding where Dumbledore was going with this.

"Sirius Black was a loyal member of the Order of the Phoenix for many years. He was also James Potter's closest friend. To me, as to many, it just doesn't make sense for him to have betrayed them to Voldemort. All the time he was at Hogwarts, Sirius hated the Dark Arts, he was the first Gryffindor in a pureblood, Slytherin family. There is also the small matter of an innocent man running from the law. If he is not a criminal, it would be unjust to send him back to Azkaban, if he is found."

"Why didn't you ask for an inquiry when he got arrested?" Crowley asked, and Aziraphale had to agree it was a good point. Though he would have put it more politely.

"I wanted to, but I was…stopped…" Dumbledore said delicately, trailing off.

"The Ministry needed a scapegoat," Crowley finished for him. He remembered hearing that Hagrid had been carted off to Azkaban after the Chamber of Secrets was opened again. Like as not Dumbledore would have lost his job if he had tried to save Sirius Black. Perhaps have been sent to Azkaban too, which would not have been useful to the wizarding community.

"But how could he be innocent?" Aziraphale cut in, bringing Crowley back to reality, "there were eyewitnesses to those murders."

"That is what I need you two to determine," Dumbledore said, "this is, I promise, in Harry's best interests. Firstly, if you catch a dangerous criminal, he will be safer. Secondly, if you prove the innocence of his father's best friend…" he seemed to ponder whether or not to tell them the next part, yet he plunged on, "Black is, by right, Harry's godfather, his legal guardian."

Another shocked silence.

"Does Harry know?" Aziraphale looked concerned.

"Not yet," Dumbledore replied, "but, with the whole thing being dragged up again, he is sure to find out soon enough."

"So, we have to track Sirius Black down, determine his possible innocence, and then, I'm guessing, convince him to work with us and clear his name," Crowley sounded slightly sarcastic, but Dumbledore didn't notice.

"Couldn't have put it better myself," he smiled warmly.

They left the office, realising too late that they had no idea where to begin their line of inquiry.

"We could check the archives," Aziraphale suggested, "of the old students. Find out who was teaching back when Black went to Hogwarts, see what they could tell us about him. It won't help us to track him down but maybe it could help prove his innocence."

Crowley nodded, and they made their way to the library, where there was a file of old students. Crowley went reluctantly. He was starting to get sick of searching through old books for information. Why couldn't Hogwarts get with the times and install a computer. It would make things a lot easier.

On arriving, they realised next that they had no idea where to start. They didn't actually even know which years Sirius Black had attended Hogwarts. They sat down, and Aziraphale was just wearily pulling a heavy box of files toward himself when Crowley stopped him, an idea springing to his mind.

"Snape," he said.

"Pardon?"

"He went to Hogwarts at the same time as Harry's father. And Sirius Black."

Aziraphale grinned.

After that, they quickly worked out what year Sirius Black had been to Hogwarts and dug up several school records from that year (being celestial beings had its perks, they just knew how old people were). They sat in silence as the lunch hour wore on, rifling through the yellowed parchment, stopping occasionally to comment on what they found.

"Lucius Malfoy was made a prefect the year he came. I guess bullying their way through life runs in the Malfoy family," Crowley said with some disgust.

Then a little later,

"Look at this angel, Lupin was in their year too. He must have known Sirius Black; we could ask him. I wonder why he didn't mention it before…"

"Maybe he just doesn't feel comfortable about it," Aziraphale suggested, "it can't be nice, going to school with someone who went on to murder people. I trust Lupin, all the same."

"I do too, but you have to admit he's hiding something."

Aziraphale did have to agree. Lupin was eager to avoid talking about his previous employment, or indeed anything much to do with his personal life.

"McGonagall was working at Hogwarts during his time there. We could definitely trust her to help us with our task."

"Will you stop referring to it as 'our task' angel, it sounds like we're going to murder someone."

"I suppose it is a bit 'Macbeth'. The play Crowley. By Shakespeare? We met the man; how can you not remember? Yes, the one who wrote 'Hamlet'."

The bell rang, and, realising they had a class, Crowley and Aziraphale hurried out of the library, Crowley still asking exactly what Shakespeare had to do with anything. They made it to their classroom with a few minutes to spare.

"Crowley," Aziraphale said quietly, as he turned into the classroom, "I just thought of something else."

"What?" Crowley hoped it wasn't to do with Shakespeare.

"We need to keep a close eye on Harry. If he finds out what Black did to his parents."

Crowley nodded, understanding at once. Harry would be sure to decide to bring justice to Black himself. It was their job to insure he didn't.

…

They didn't get a chance to speak to Harry about Professor Trelawny until Thursday, when they agreed to ask him to stay behind after the Defence Against the Dark Arts lesson. Meanwhile, the school was buzzing with excitement about Lupin's first Care of Magical Creatures lesson. Apparently tackling boggarts had gone very well indeed. The Third Year Gryffindor class in particular were telling anyone who would listen about Snape in a dress. Crowley was impressed by Lupin, though he thought that bringing Snape into things was unwise. Snape had already seemed to dislike Lupin, before the lesson in question. According to the records, they had been at Hogwarts in the same year. Crowley knew that Snape had hated Harry's father from their time at school, why not Lupin too?

After the lesson, Harry stayed behind, looking worried. Aziraphale had decided that it would be best for Crowley to speak to him, as he had taken the lesson that day. The demon had argued passionately against the choice, but Aziraphale had promised to speak to Snape that weekend, and Crowley wanted to do that even less.

"You asked to see me Professor?"

Crowley shifted awkwardly, trying to come up with the right words.

"I wondered Potter, if you are alright," he said finally.

He had not chosen the correct thing to say. Harry looked mutinous.

"Is this because I passed out on the train?" he asked, "because I keep telling everyone, its nothing."

"No, no," Crowley replied quickly, "I had forgotten all about that. It was about…about Professor Trelawny."

"She predicted my death," Harry looked at the floor.

"Yeah, I know. Umm," Crowley wished he'd agreed to take on Snape now, "I just wanted to tell you that…well, don't take it to heart. We're all going to die, it's nothing special."

He deeply regretted the last bit, but it seemed to cheer Harry up a little.

"I hadn't thought of it like that," he admitted.

"You're not going to die any time soon," Crowley said, buoyed by his unexpected success.

Harry looked pensive. Then he said,

"Professor, you wouldn't think I'm mad if I said I'd seen something…something odd? It's just, I kept hearing the Basilisk and I thought I'd gone mad but, you could hear it too so…"

He shrugged.

"What is it?" Crowley asked tentatively.

"I saw a big black dog, the night a ran away from home. And Professor Trelawny and Ron and the others, well, they say it's a Grimm. A death omen."

"I really doubt that," Crowley didn't think before he said it, so rushed to explain, "I mean, there are a lot of black dogs around. Most of them are quite nice really."

He thought nostalgically of Dog, the hellhound.

Harry nodded thoughtfully. Crowley decided that now was a good time to end the conversation.

"Err, that's all really Potter," he said, "let me know if you see any more dogs. Or, you know, anything else."

Harry thanked him and left, looking happier than when he had arrived. On the whole, Crowley thought, that hadn't gone too badly at all.