Chapter 1

Sirius Black leant back and looked out of the window. The trees were rushing past, much the same as they always did in the Hogwarts Express. In front of him, his best friend, Remus Lupin, was fast asleep and snoring lightly. He still could not believe that the war was over, and all was back to normal. He smiled humourlessly as he realised that he did not know what 'normal' was anymore.

Of course, as with any war, there were casualties, and with them came pain. He thought, with a shudder, about how much of his own year at Hogwarts had been wiped out. James and Lily, his best friends, together in life and death. And then there was Dumbledore. With Dumbledore's passing, it had felt as though the last spark of hope had been put out. Sirius was sure each member of the Order had felt it, though none spoke about it. There was an unspoken agreement that each of them would give their life for the cause, as so many had.

But Harry had made sure that Dumbledore had not died in vain. His heart swelled with pride as he thought about his godson. The boy had really come into his own during the war. He had proven that he was a true Gryffindor, just like his father. Harry and his friends had set out on the mission given to them by the former headmaster, refusing to share the details with anyone, until the final battle.

It had almost broken him when Harry had told him that he needed to die in order to kill the dark wizard, and he would have put the boy in a full body bind to prevent him from foolishly rushing to his death, but his godson beat him to it.

Sirius had laid there, helpless, as he watched Harry walk towards death. But somehow, once again, against all odds, the boy had survived.

And they were successful. So successful, in fact, that Voldemort had been vanquished once and for all.

It almost didn't feel real that, just a year later, here he was on the way back to Hogwarts, as a teacher. Sirius Black, the largest prankster of his generation, teaching Transfiguration! The thought was laughable. And Remus back with him. It was the life he had never dared to imagine for himself.

Remus Lupin opened his eyes as his friend shook him awake.

"We're almost there, mate," said Sirius, unable to keep the almost childlike excitement from his voice. "I thought you'd probably want to be awake before we see the castle."

Remus smiled gratefully, and rubbed his hand across his eyes and Sirius thought he looked younger than ever. His beloved wife and child were safe at home, he finally had a job he could rely on, and with Shacklebolt becoming Minister and investing huge amounts of Ministry funding into researching developments to the Wolfsbane Potion, there had been an almost sudden shift in the public views on lycanthropy.

Sirius must have zoned out for a moment, because Remus, scoffing a sandwich down with one hand, was waving his other hand to get his attention. He nodded towards the window of the carriage, and both men sat, just as mesmerised by the first glimpse of the castle as they had been aged 11.

Just looking at it now, it was impossible to tell that anything had ever happened. There had been a huge effort over the past year to repair Hogwarts before the beginning of the school year. The only reminder of the events of the war was a fountain carved out of marble, a memorial to those who had fought valiantly on these very grounds to make the world a better place. It was in the shape of a phoenix, magically charmed to burst into flames at the end of every school year, and grow back by the start of the next.

The train came to a halt, and the men got out and began to make their way towards the castle which they would be calling home for the year, but which both had secretly considered to be their home since they had first stepped foot in it.

Severus Snape made his way towards the gates, to ensure that the older students did not get 'diverted' en route to the castle. After all, he thought to himself, there were many 'diversions' for hormone-crazed teens of their age. The thought made him shudder.

Over the past year his time had been divided between the Ministry and St Mungo's. In fact, it was only in the past month that the ministry's investigation had concluded and just last week had he been told that he no longer needed the weekly check-ups with his healer. He had been advised to continue to attend therapy sessions, and though he had made a point of complaining about it, he had secretly been quite pleased by this. His Psych-healer Titus Maxwell was a gentleman not more than 20 years his senior. He was a practical man, to the point, and always listened attentively before giving his own thoughts. Severus had to admit, he liked the man and enjoyed being able to speak freely under oath of confidentiality.

He gently massaged his neck as he walked, the scar from Nagini's bite still prominent. He was still having some difficulties with balance and coordination, and he made a mental note to mention it to Maxwell at his next appointment.

He wasn't convinced that he was ready to resume his teaching duties, but both McGonagall and Johnson clearly thought otherwise, and he had reluctantly agreed. truth be told, he was more concerned about the students' reaction, but to his surprise, most of the older students had inclined their head at him with respect, as they passed him, some even braving a small smile. He caught sight of two familiar figures making their way towards him, after the students had passed. Lupin and Black. How could he forget that they would be here too, this year. Lupin smiled at him as they neared.

"Good to see you, Severus," he said, extending his hand, which Severus shook curtly.

"Lupin. Black."

"Yes, hello Snape," Sirius said, shortly. Severus didn't expect the two of them to ever be friends, but he nodded, face emotionless. The childhood enemies shared a look, both assessing the other. Severus didn't have the energy to hate Black any more.

"See you in the feast, then." Lupin was still smiling as they walked past him towards the back of the train, to fetch their luggage. As they left, Severus wondered absently what Lupin had done during the full moons in the last few years. Lupin had always been civil, friendly even, with him, although he had perhaps more reason to hate Severus than most (it had been Severus, after all, who had exposed Lupin's condition to the wizarding community). He sighed. Maybe he was going soft, but he resolved to learn the newest recipe of the Wolfsbane Potion, and work on improvements of his own.

On his way back, he ran into Flitwick, who was preparing to usher the new First Year students into the castle. There were twice as many new starters this year, and Flitwick was looking as nervous as ever in anticipation. "Ah, Severus, there you are, I've been meaning to have a chat with you," Flitwick said to him, eagerly. "It's about an opportunity which has recently come up, that I believe you might be interested in."

"An opportunity?" Severus asked, a little intrigued.

"Well, as a matter of fact, the British Charms Colloquium is to be held this winter, just a week-long event, with talks from various wizards from around the country. Would you be interested in speaking?" Severus frowned.

"What would I speak about there?" he asked. Surely Potter hadn't- Flitwick cleared his throat.

"Ah, well, actually, and don't blame Harry for this, but as it turns out, he may have mentioned the some of the charms you created as a child," Flitwick said, sheepishly. Bloody Potter, thought Severus. The boy had been a recurring feature of his year, and he was becoming increasingly difficult to dislike (much as Severus tried). He had even confessed to Healer Maxwell about feeling an uncomfortable sensation when Potter was around, which Maxwell seemed to think was a combination of gratitude and guilt. Despite the way Severus had treated him throughout his time in Hogwarts, Potter had not only saved his life but also helped cement his freedom by testifying to his innocence.

Flitwick seemed to think he was still pondering the offer. "Look, you don't have to decide now. I need to send my application off by the end of the month so have a think about it, will you? Though I really would like to hear about the Muffliatus charm at some point! Truly remarkable!"

"Very well," Severus conceded, steeling his face into a blank expression, but feeling his ears go pink from the flattery. He turned away to see a third year Ravenclaw student stumbling over and nearly bringing two other students down with him. "Watch where you're going, Mr Trent!" Jimmy Trent, alarmed to have been spoken to at all, stopped dead in his tracks and whirled around to look in Severus' direction, causing another student to walk into him. Severus sighed and shook his head and heard Flitwick chuckling next to him.

As Remus and Sirius retrieved their luggage, they ran into Hagrid.

"Yeh 'right, boys?" asked the half-giant.

"We're great, Hagrid," replied Sirius. "Are you alright? You look worried."

"Oh, you know what today's like, all those firs' years ter keep track of, more so th'n usual! Speakin' of, best be goin'!" Hagrid hurried away and the two friends grabbed their suitcases and began to head in the direction of the castle.

"So all these years later, we're back at school with Snape," Sirius said, suddenly. Remus looked at him apprehensively. "Before you say it, Remus, I'm well aware of the sacrifices he made for the Order. I'm just saying, it'll be weird."

"It might be weird if we were children, but we are all adults," Remus said, with a pointed look. "We can treat each other with respect."

Sirius waved a hand dismissively. "I'm surprised he even wanted to come back to teach. From what Harry used to tell me of him, it sounded like he hated the job."

"Well, perhaps he has changed. We all have after all."

Actually," Sirius ignored him, pondering. "Now I think about it, I'm quite surprised McGonagall asked him back. Surely the kids need their teachers to be supportive, this year more so than ever!"

"I don't want to have this discussion, Sirius," Remus interrupted. "The Headmistress has hired him, I respect her decision, and you need to let go of childhood grudges."

Sirius agreed reluctantly. Perhaps he was getting old - he was well aware he would be turning 40 in the next few months - but truth be told, he had been struggling recently to maintain any strong hatred for his old rival. After all, he too had seen those memories along with the rest of the Wizarding community (something he was sure Snape was none too pleased about). All the same, he couldn't help remembering how dejected Harry had seemed after his Occlumency lessons with Snape, and resolved to keep an eye on the man through the year.