A/N: Alright, this is my first work of FanFiction. The scenario is pretty overused, but I quite like it, so I decided to give it a try anyway. I am very glad about any kind of review that I get, even flames, though I hope that that's not all I get.

I will try to stick to canon as much as I can, but because this story features time-travel, it will necessarily be somewhat AU-ish in some places. Any ideas as to how I could make this story closer to canon are welcome.

Disclaimer: I DO NOT OWN HARRY POTTER. All the characters and places that you recognize are J.'s creation. The plot's mostly mine, though I will let some parts of her books flow into this as well.

Back in their Day

Chapter 1 – The Arrival of the Stranger

"All the new faces – welcome at Hogwarts! And to all the old ones, welcome back! A few things before the feast, after which you are probably to full to listen to an old man talk." As Dumbledore said this, many people grinned – that was just typical Dumbledore, to insult himself in such a pleasant manner. "As always, I want to remind you that the Forbidden Forest is forbidden to enter – as the name should suggest, really." The piercing blue eyes of the Hogwarts headmaster flashed over the crowd, resting on four seventh-year students a fraction of a second longer than on the rest of the Great Hall, who was pretty much as an entity looking at him. Two of the four boys, of which one was rather short, but athletic-looking boy with messy black hair, hazel brown eyes and round glasses, whereas the other was tall and wiry, with his shoulder-long black hair falling elegantly on both sides of his head and his gray eyes twinkling in amusement, just as those of his friend were. The third boy, a tall and rather peaky looking youth with sandy-coloured hair that had already begun to gray at his temples and kind amber eyes, was completely unfazed – he seemed to have drifted off into a light sleep. The fourth of the group, a pudgy boy with a pale face, watery eyes and mousy-brown hair squirmed slightly as the Headmaster gazed upon him, although there was nothing accusatory in his gaze, rather concern paired with amusement.

After Dumbledore had waited for a few seconds, he continued his speech. As soon as the Headmaster's gaze left him, the boy with the black, messy hair shifted his gaze from the headmaster to a very pretty redhead that was sitting a few feet down the long table he was seated at as well. She was quite tall, with a slender figure, had a kind face and curves in exactly the right places. However, what ensnared him most of all were her eyes. They were almond-shaped eyes in a piercing emerald green. He sighed dreamily and, with all his might, focused his attention on the Headmaster, absent-mindedly fumbling with a small silver badge on his robes.

"…has been expanded to a number three-hundred twenty-five. All of those interested in what these objects are, feel free to check out the list that can be viewed on Mr. Filch's door." The elder man paused for a second and, for the first time since the beginning of his speech, looked his age. "I also have more serious matters to discuss - ("Cool! That's about me!", the boy with the elegant black hair cried out, joyously, which caused his friends to groan and the boy with the sandy-coloured hair to smack him on his head.) - but that can wait until after the feast. Tuck in!"

Most of the student population didn't need to be told twice and they dug into the food that had suddenly appeared on the tables at various speeds. Conversation ensued, mostly focusing either on the holidays of the others or the mystery issue that Dumbledore wanted to address after the feast. When the last speck of dessert had vanished, Dumbledore stood up again, looking rather old again.

"Now, I regret to have to inform you that I have not yet been able to find a suitable Defense Against Dark Arts teacher. I will continue my search of course, but - "

"No, you won't." A quiet yet perfectly audible voice sounded from the entrance of the Great Hall. Everyone spun around, shifting their attention to the new arrival. Standing in the doorway was a tall, young man who appeared to be slightly above Hogwarts age. He was wearing a long black travelling cloak that was flapping around his ankles as a sudden breeze swept through the open door into the hall. His feet were, unlike with most wizards, not clad in boots, but in plain black Muggle sneakers. His hood was pulled up, therefore his facial feature were invisible to the people of the hall. However, everyone instantly sensed that this man was a wizard of great power – he was radiating it like heat. Instantly, Dumbledore, McGonagall, Flitwick and Slughorn had their wands trained upon him.

"Who are you?" The Headmaster asked in an even voice, though one could hear that it shook ever so slightly if being very familiar with Albus Dumbledore. He was obviously contemplating the possibilities concerning the arrival of this mysterious stranger and, being in war times, automatically jumped to the worst conclusion. If the stranger should attack, then there could be casualties amongst the students, something that the elder wizard sought to avoid at all costs.

Although nobody could be sure, many people would, when asked about this incident later, proclaim that the man was smiling when he answered. "I have come to apply for the Defense Against Dark Arts position, which, as you just said yourself, is still vacant." Some of the teachers and a great deal of students starting mumbling amongst each other, but if Dumbledore was shocked, he masked it well.

"How can I be sure that you are no supporter of Voldemort?" He expected the mysterious man to flinch like next to everyone in the hall did, but he didn't even seem to notice that Dumbledore had just uttered the name that nearly every wizard of the country feared. The new arrival didn't answer, however – he simply pushed up the left sleeve of his cloak, to reveal a pale, muscled arm that was disfigured by many scars, gashes and cuts. Not many people knew what this was supposed to unveil – what could a scarred arm tell the Leader of the Light and Hogwarts Headmaster about the loyalties of the man that was standing in the entrance? – but whatever it was, Dumbledore seemed to accept this, as he nodded.

"What are your qualifications? You seem to, forgive me for putting it bluntly, be very young to be a teacher." This time the arrival was definitely smiling, for amusement was evident in every syllable of his answer.

"Well, I am eighteen, but I think we agree that not age, but qualification is relevant for this job, isn't it?" The man raised his voice ever so slightly during the second part of the sentence to make himself audible above the crowd, who started to speak in hushed voices upon hearing his age.

"Indeed it is." Dumbledore answered, nodding. Upon noticing that his wand was still trained upon the arrival he lowered it, causing his colleagues to do the same. "Forgive me. So, what are your qualifications?"

"Do you want to see for yourself?"

"What do you mean?" The elder wizard asked, sounding a little confused for the first time.

"Let's duel."

In a matter of a split second, the hall went deathly quiet and all the people who had turned to fellow students or colleagues for talking snapped their heads at the new arrival, expecting him to be joking of some sort – clearly he couldn't hope for a victory against Dumbledore? But nothing of his appearance seemed to show that he was joking. His eyes (though no-one could see them) were boring into the Headmaster with a ferocity that everyone felt, who looked genuinely surprised and disconcerted. But after a fraction of a second, he quickly arranged his face in a nonchalant mask and smiled at the young man in the doorway. "Of course. Let's go to the Entrance Hall, shall we?" The man nodded once and Dumbledore stood up, after walking around the teacher's table, crossed the hall in quick strides. This seemed to break the ice and the students started whispering again – this had to be a feast full of firsts, as nobody could remember Dumbledore having ever interrupted the Opening Feast before. Students and teachers alike stood and followed the man with the flowing beard out of the Great Hall into the large Entrance Hall, where they spread around the room, leaving a space in the middle where the two duellers were circling each other already. When everyone had filed out of the Great Hall to watch the spectacle, the mysterious man waved his wand once and a silver cage expanded over him and Dumbledore.

"It absorbs all curses, so that no-one gets hit by a stray curse." Dumbledore nodded, looking thoroughly impressed and pulling his wand from his midnight-blue robes.

"What are the curse restrictions?" The Headmaster asked in a very professional manner, leaving no doubt that he had once been a professional duellist.

"No Unforgivables." Was the curt answer he received from the stranger. He waited for him to continue, but he didn't say anything more than that. Instead, he raised his wand like a sword and bowed to the Headmaster, who mirrored this gesture a split second later. As they both raised their heads again, Dumbledore attacked first, shooting a silent stunning spell at his opponent, who deflected it with a lazy flick of his wand, only to retaliate a split second later in equal silence. He shot a jet of blinding white light that no-one recognized at Dumbledore, who erected his shield just in time to stop it, though he swayed on spot slightly. However, instead of using this momentary moment of weakness, the stranger merely brought his wand down, without a visible curse being shot at Dumbledore. Seemingly nothing happened. Only a loud crack overhead told the spectators as well as his opponent what he had done – one of the torches on the wall behind him had been wrenched out of its haltering and was now hurtling at Dumbledore at an amazing speed. However, the Headmaster had regained his control in the fraction of a second that the stranger had given him. With one fluid wave of his wand, he banished the torch, over the heads of the students and teachers that were watching in awed silence and conjured a fiery whip that slashed across the stranger, who hadn't brought up his wand in time – obviously, he had not expected that Dumbledore would defend and attack with one wand movement. However, he did not crumple as the majority of Hogwarts had been expecting, but raised his left hand in a fluid cutting motion, like a knife. The fiery whip lashed out and fell to the floor, still writhing – it had been cut cleanly into two. Dumbledore, too shocked by this move, didn't even try to defend himself against the last attack, a Disarming Spell that had been fired not even a second later. It hit Dumbledore and his wand sailed out of his hand and into that of his opponent.

A shocked silence followed this breathtaking duel. Nobody had ever seen Dumbledore lose a duel, or rather could have imagined this happening (most people had never him in a duel, anyway). Then, like lighting a fire, awed muttering broke loose among teachers and students alike. Dumbledore, however, had already regained his composure. He was smiling warmly at the mysterious man in the black travelling cloak that was still wearing his hood.

"Congratulations. You're hired." Was all that the aging headmaster said. "What's your name?"

"Ethan Jameson." The stranger said, hesitating for a split second, something that Dumbledore and the amber-eyed youth in the first row noticed, whose eyes narrowed. Whispers broke out again, this time more loudly than before, but even the people with the best connections to the Ministry had never heard this name. Who could this be? A wizard, more powerful than Dumbledore that they had never heard of before? Dumbledore, whose eyes were twinkling like mad again, turned his focus from Ethan Jameson and faced the pupils.

"I think that that is all. You may go to your dormitories. Sleep tight!" Not many students favoured being dismissed like this, especially after this breathtaking performance, as they all wanted to know more about Jameson, but no-one, not even those certain members of the Slytherin house who sneered upon Dumbledore dared to disobey an order from him, for no matter how friendly he had worded it, it was clear that it was one. As the prefects led the first-years out of the Entrance Hall, along with the older students (though some of them took shortcuts), the Headmaster turned on Jameson again. "May I speak to you in my office?" He said, his blue eyes piercing into the still-hooded man, standing there in the middle of the Entrance Hall. Said man nodded and, with a wave of his wand, the silver cage disappeared. Meanwhile, the Entrance Hall (with very vocal aid, courtesy of Professor McGonagall) had nearly emptied already and, after bidding the remaining teachers good night, the two men strode up a staircase at their right.

"Did you see that?" The chubby boy with the mouse-brown whispered to his friends as he pulled a tapestry showing a Paracelsus brewing a potion of a rather nauseous colour. He was obviously awed by the skill that their new Defense teacher had demonstrated. The boy beside him pushed his silky hair out of his vision with casual elegance that would have made every girl swoon, had there been any present and rolled his eyes at his friend's question.

"Obviously, Wormtail. We were standing right beside you." As Wormtail blushed, one of the two boys just behind them clapped the speaker onto his shoulder, causing him to be whirl around and to stare into his hazel-brown eyes behind the round glasses. He was looking at his friend with what should be a disappointed look, but said boy didn't quite manage it.

"Now, now, Padfoot. Be nice." He mock-chastised, though the effect was somewhat ruined by the insincerity in his eyes. Truth be told, he was just as amazed by his new teacher just as much as his friends were. But there had been something else. He couldn't quite place it, but the teacher had given him the impression of knowing him from somewhere. But from where would he know him and why wouldn't he remember a wizard of such prodigious skill, even if they had met before? Well, maybe he could work it out the next day, when they had their first DADA lesson with him. He turned to the fourth member of the group, whose eyebrows were furrowed – he appeared to be deep in thought.

"What's up, Moony?" The boy asked him, ruffling his black, messy hair with his hand, succeeding only in making it even more messy.

"I don't really know." Was the answer that he got. "It's just… did you notice that he hesitated before saying his name?"

"What d'you mean?" Padfoot asked, who was listening to their conversation with one ear, just as they turned a corner and could see the portrait of the Fat Lady at the end of the corridor.

"I have no clue. But… you don't really stutter with your own name, do you?" Finally getting what Moony was hinting at, Padfoot snorted.

"You think he's got a false name? C'mon Moony, that's bullshit."

"Doesn't have to be. Maybe he's… I dunno, a target for the Death Eaters or something… I mean, he's powerful to have them interested him, isn't him? And…"

"…he changed his name to disappear." The boy with the messy hair concluded. "That could be."

"Yeah. If you ignore the fact that he just turned up at a place where You-Know-Who has spies." Wormtail objected, surprising the others. He always appeared to be a little slow sometimes, but he had quite extraordinary amounts of insight in some topics.

"You're right, Pete." Moony said, frowning again. "That doesn't really make sense."

"Well," Padfoot began. "we might find out more tomorrow. You know, in class. I'm too tired now, to be honest."

"That's just an excuse 'cause you can't think." The messy-haired youth teased. Moony and Wormtail snickered lightly while Padfoot pouted.

"Harsh, Prongs. Harsh."

"Oh shush. Epiphany." The last word was directed at the Fat Lady, who nodded at the four of them and swung forward to reveal a small hole behind it, through which the four boys climbed. They passed through the comfy Common Room and walked up a staircase at the far end of the tower, where they found a circular room with five four-poster beds. Their luggage had already been brought up to their rooms, so they merely got their pyjamas out of their trunks, brushed their teeth quickly and fell onto their beds, too tired to continue their discussion any further. They fell asleep even before their fifth dorm-mate Frank Longbottom had entered the room.

"Well, Mr. Jameson. Do sit down. May I offer you a drink?" Dumbledore asked the younger man pleasantly, who had settled down on a chair in front of him.

"No thank you, Sir."

"Call me Albus, now that we are colleagues."

"Alright, Albus." said Jameson, finally pulling off his hood to reveal his face. It was severely scarred in many places, the most eye-catching one being a very fine scar on his forehead, in the shape of a lightning bolt. His black, shoulder-long hair, which was messier than that of Padfoot, though, was pulled back into a ponytail. His eyes were blue, but somewhat dull and lifeless, as though they had suffered through too much pain to carry on. Dumbledore eyed him critically, his eyes resting a tad longer on the scar on his forehead than on his other features.

"Can you tell me a little about yourself?" He inquired, once he had finished his scrutiny. Jameson hesitated, then nodded.

"But this has to stay between us, alright?" Dumbledore nodded, wondering what Jameson wanted to tell him that of such importance.

"My name is not really Ethan Jameson. My name is Harry Potter."

"I see. Are you related to James Potter, a Seventh Year Gryffindor, by any chance?"

"Yes, I am." The man said. He hesitated again, then he spoke again. "I'm his son."