Disclaimer: It's not mine. If I could just have temporary loans of Remus Lupin, I will be happy.

A/N: You may notice that this is a re-post. It's an idea I really love and I didn't do it justice last time.

A/N: Oh and there are little links to my other stuff because I like to keep all these stories in the same universe, but they're not important.

The silence on the first floor was eerie and Harry felt a shiver run down his spine. There was no-one in sight but he didn't much care for the feeling of being watched. He could attempt to blame it on some of the portraits but they didn't usually produce the same feeling of vulnerable helplessness.

He heard the sound of footsteps and a short, sharp intake of breath. He swung round and was sure he saw a mass of shaggy, unkempt black hair. He took a deep breath. "Potter, you're paranoid," he assured himself.

All the same, he ran the rest of the way to Lupin's classroom and seemed to make an attempt at smashing the door down with his fist.

Lupin eventually answered, standing now in the same patched suit he had worn on the train. Harry assumed this was what passed for leisure wear. He raised his eyebrows and looked beyond Harry. His eyes returned and settled on Harry's face, looking into his bright green eyes.

"Well, Harry, I think there was someone on the seventh floor whom you failed to disturb. Would you like another try at it?"

Despite his earlier panic, Harry grinned. "Sorry sir."

"Quite all right. I probably wouldn't have heard you if you hadn't," Lupin admitted. "I was in my office. I was expecting you to go straight there." He ushered Harry out of the room and into the corridor. "It's closer to your common room," he added, catching sight of Harry's puzzled expression.

"You said 'lesson' so I thought I should come to the classroom," said Harry, wondering whether to tell Lupin what, or who, he thought he had seen.

Lupin smiled. "No. I don't know if you've seen my classroom lately but it's not the neatest room in the castle and to be quite frank, it's half past eight on a Thursday night and I have better things to do than start cleaning my desk. It's my own fault entirely. I just like clutter." He cleared his throat. "So I persuaded Professor Binns to give us a loan of his room for these lessons. You'll be pleased to know I've found an excellent Dementor substitute."

Hidden behind a statue, Sirius Black watched this scene intensely. He had never seen his godson interact with anyone before and a conversation with Remus Lupin was one that he had a great deal of interest in.

He waited for Harry and Lupin to disappear from view before he risked emerging.

He crept up to the Defence classroom and read the bronze plaque bearing classroom information. It was decidedly odd to see 'Professor R. J. Lupin, Defence Against the Dark Arts, 3C' on the door.

Beneath it was a small wooden square hanging from a nail that had been nearly hammered into the exact centre of the door. This was the handiwork of a man with an acute compulsive disorder. This had to be the handiwork of Remus Lupin.

'A tidy classroom is the sign of a wasted life'.

Black recognised it. It had been a Christmas present from Lily - one she had given in 1980 when Lupin was acting his way through Maths lessons in a Muggle Primary school. The blind were truly leading the blind when it came to subtracting fractions.

He wondered how Moony was doing. It couldn't hurt to just look for a few moments, could it? Lupin wouldn't mind him going through his things anyway, he never used to mind. Or at least, he never used to have the courage to voice his indignation.

Black laughed bitterly, knowing there was no-one to hear him, and pushed the door open. He found himself stood inside a dimly lit room, directly under a dragon's skeleton.

Perhaps, he thought, he was now too used to small spaces but this classroom seemed to be much larger than he remembered it. He glanced around the empty floor space and it dawned on him that the reason for this was that Lupin had piled the desks up against three of the walls.

The fourth wall was hidden by a row of bookshelves that reached the ceiling. The Defence Professor, it seemed, could open a library and easily rival Madam Pince. This, Black just knew, was a only a small percentage of the books Lupin had brought with him.

He ignored the bookshelves for he had found something far more interesting to him.

Lupin's desk sat at an elevated position, giving him a bird's-eye view of his students. It was kept in organised chaos, several pieces of parchment had been stacked high and a half-full coffee cup seemed (bizarrely) to be in use as a paperweight.

It was not until he was sitting in Lupin's chair and looking out at the empty, dimly lit classroom that he met a pair of eyes and leapt to his feet, stolen wand at the ready. He had never used it before and couldn't help but wonder whether this was going to backfire hugely.

He sighed with relief when he realised that the eyes belonged to Lupin's latest zoological subject - a Moke.

"You scared the shit out of me," he croaked at it.

Black's voice was harsh and sounded as though he had been smoking on a regular basis for thirty years. He rasped when he breathed. He could hear why people were so scared. He even sounded like a murderer.

In response, the Moke shrunk to a mere inch in size and peered up at him.

Black rolled his eyes. He should have known, he thought, that he would find at least one odd pet in residence.

Ignoring the Moke, he inspected Lupin's desk. The coffee cup steamed and the smell alone was a little slice of heaven. It was bound to be too milky and so full of sugar that it had the consistency of treacle, but Black still found himself sipping it slowly, nursing the cup.

He shuffled the papers, reading assignments that Lupin had evidently been halfway through marking when Harry chose to call on him. Red ink lay splattered on the oak desk and Sirius licked a finger and began to scrub it off absentmindedly.

It was only when the ink was a faded mark that it occurred to him that he oughtn't have touched it.

He tapped the stain with the peacock feather quill Lupin had left strewn across the parchment and flicked more ink onto it. There. Barely any difference if he said so himself. A genius plan.

Black frowned and held the quill up to the flickering candlelight. He recognised it with reason. It had been a present for Lupin's sixteenth birthday. It was a Hogsmeade weekend the Saturday before and Lupin had stared at it for what had felt like hours before wandering off, muttering about low rates of pocket money and saving holiday money for Ireland.

James had watched him walk away, waited for his mop of hair to bob around the corner, snatched the quill and had it gift wrapped in the shop with only the words, "Finally, I'm going to beat Moony in the tidy wrapping stakes."

Sixteenth? Black laughed bitterly, his voice echoing around the room. Sixteenth birthdays were only half his lifetime away. It felt as though he and sixteen year old Padfoot were distant cousins living in separate worlds, light-years apart.

His eyes scanned the parchment and his heart stopped, sinking rapidly into the pit of his stomach.

"Cara McCormack.

The Ramora is a fish with silver scales that makes its home in the Indian Ocean. It is known as a guardian of seafarers and…"

Black stopped reading. The words "William proposed. William McCormack. How many Williams do we know?" echoing in his mind, her voice warping into the mocking tones of Bellatrix who had heard every word of his first and last visit as she spat at him through the bars of her cell. He was shocked at how little he remembered. He could not even recall the accent of the woman he supposedly loved.

He had kept himself sane in Azkaban, repeating a constant mantra.

I am Sirius Black.

Somewhere along the line, he had forgotten what that actually meant.

He wondered if Lupin felt the same, watching her every day, marking her essays, handing out House Points, knowing whose daughter she must be.

Distracting himself, he pulled out the drawers of Lupin's desk and tried to forget what he had read.

Ink. Parchment. Several spare quills. Chocolate Frogs. Nothing of any real interest.

Black helped himself to a Chocolate Frog and read Agrippa's card. He wondered if Lupin still collected these and, remembering that Agrippa was rare, placed it neatly back in the drawer, wishing he could catch sight of Lupin's face when he spotted it. Shock, maybe? Horror, perhaps? Confusion, definitely.

The next drawer was locked. He whispered "Alohamora" and was shocked to find it still refused to budge.

"What's Moony hiding then?"

He smirked and headed out of the classroom, up the twisting staircase into the Defence teacher's office and quarters.

Lupin had chosen crimson coloured walls and a thick white carpet, reminders of his bedroom as a teenager, Sirius assumed. Certainly, it looked almost exactly the same. He had pressed a bed up against the wall and shoved boxes overflowing with books under it.

The bedside table was cluttered with a candle, three books, a packet of tissues, a large bottle of what Black hoped was water, and a water filled tank containing a disgusting looking fish.

The walls were covered with their photographs. He and James standing in front of an orange lake with guilty smiles. He and James leaning on shovels before a great hole in the school grounds. James and Remus lying by the lake, the ever-present Snitch hovering just out of James' reach. He and The Rat drenched to the skin having thought a little swim in the November moonlight would be refreshing.

He couldn't stand to look any longer and reached out, taking a photograph of the four of them, arm in arm and smiling, laughing at the camera and never imagining they would break apart, distrusting one another, mistrusting one, amidst rumours of spies and murder.

A kettle sat on the windowsill beside pots of teabags and sugar and a large bar of chocolate.

Black helped himself to several squares of the latter and flicked through the titles on Lupin's bookshelves.

Fantastic Beasts and Where to Find Them, that would explain his seemingly inexhaustible supply of creepy looking subjects for his lessons.

Defensive Magic: The Basics.

Defensive Magic: Advanced Level.

Grindylows: The Hidden Danger. Lupin really was the only person he knew who could actually enjoy an exposé about bog dwellers.

Jenny Greenteeth: Witch before Woman? That sounded awfully like the title of a horror novel.

Hinkypunks: The One Legged Wonder.

Black couldn't help but bark a laugh in response.

How he missed Lupin. He missed the sense of humour. He missed the energy. He missed the optimism. He missed the quirky dress sense. He missed the quenchless thirst for knowledge. He missed trying to drag Lupin away from bookshops, libraries and armchairs by the fire with a thick book and a large bar of milk chocolate. Come to think of it, he missed the relentless quest to find chocolate too. He even missed the rationality, the moments of genius, the spells that Lupin knew to get him out of all sorts of trouble.

He missed Remus Lupin more than words could say.

He heard the door click downstairs in his old friend's classroom and Black froze. He could wait and explain himself, hoping against hope that it was indeed Lupin who would trudge to bed and receive the shock of his life, or he could run.

And Black was not surprised to find himself in the Forbidden Forest, in his true form, leaning against a tree, his knees pressed to his chest as he wished he had had the courage to stand and face Lupin.

He liked to think himself brave. He had never ran from anything before, not even Azkaban. He had stood and waited, laughed even, as the Ministry Officials surrounded him.

It was Azkaban, he thought. He was so terrified of it, of going back to it and never being able to make a second escape, that he couldn't stand his ground and at least attempt to explain himself.

"Not yet," he whispered, almost enjoying the sound of his voice carrying on a blustering wind, too familiar with the sound of its echoes on stone walls.

He hadn't explained himself or cleared his name, but, he reminded himself, the best laid schemes of dogs and men gang aft agley.