Prologue
A/N - Okay, guys, so I'm going to ignore the "nineteen years later" thing and just write this as if it never happened. Sorry if I suck at writing this, by the way – I haven't written anything in forever. Tips and brit-picking are greatly appreciated! Nagging me to write is also appreciated!
Nobody had expected for peace to last for such a short time. Surely, since The Boy Who Lived – Harry Potter – had defeated Voldemort, peace would come about for at least a half a century. The greatest dark lord to arise in centuries had been defeated and his forces killed or captured. Sadly, Tom Marvolo Riddle – or what little left of him existed – had been vanquished. He was dead, very dead, and in his wake he left a recuperating nation and a massive opening for dark wizards. There would always be someone seeking to gain power, to hurt others, and thus from the ashes rose a new power, nearly as great as the last. Few knew her name, for she worked from the shadows. All that the wizards of Britain and their surrounding countries knew was that people were dying, obviously murdered, and nobody knew who was doing it. That's why the attack on Harry Potter's twenty-first birthday was a massacre, as well as a massive blind-siding.
And so began a new age of terror, but this time Harry and his remaining friends had a plan. A reckless plan, of course, but definitely a plan. Harry planned to do the impossible, to go where no wizard had gone before. He, and the rest, planned upon sending an entire box full of notes on what was going to happen, why, and how to stop it. Surely, nothing could go wrong with such a dangerous and potentially universe-destroying (I mean, this could cause a paradox. That stuff can be pretty dangerous.) spell that would send a box flying through time to the first day of Hogwarts, directly on Dumbledore's perfectly cooked steak, courtesy of the house-elves.
Not long after this, the new dark lord came out of the shadows - a woman by the name of lord Yanstra. She idolized Voldemort in many ways, and shared traits with him as well. Despite her almost comical idolization of Tom, and her odd name, she was nothing to laugh about. With her dark and more cult-like following than that of Voldemort's, she killed many people, not in any small part due to the instant complacency of the Wizarding world following Voldemort's fall from power in the castle of Hogwarts.
And so we begin in a circular room, shaped in a most peculiar form to concentrate magic. This room had been built long ago, near the castle of Hogwarts, to focus the strength of the powers of the greatest wizards of that millennium – Rowena Ravenclaw, Helga Hufflepluff, Godric Gryffindor, and Salazar Slytherin. The founders of Hogwarts did great things in that chamber, but they never did anything quite as extraordinary as what Harry, Ginny, Hermione, Ron, George, Luna, Neville, Seamus, and Dean were about to do. Seamus and Dean hadn't been expected to join the group, but since they had been in Harry's year with Ron and Neville, they were allowed to join them in casting the immensely draining spell.
The rest of the old DA and the few remaining members of the Order of the Phoenix waited outside the entrance to the hidden chamber, defending the casters of the spell as they cast the spell that would alter time itself. They knew that this time, there was no winning. Yanstra had no fatal weakness to anyone, and she had horcruxes of her own. Nobody knew how many, but it was certain that she had at least two. This war they could not win, especially not with the devastating blow that started off the war. If this didn't succeed, a large amount of Europe would be taken by Yanstra, and from there she would only grow in strength.
Harry sat down with his head in his hands, looking up to see Hermione begin to trace the lines on the floor with her wand leaving glowing trails where it touched, all the while muttering calculations to herself. What she was doing involved incredibly complex arithmancy, and one small mistake could result in all of them blowing up, being turned into trees, or the box not being sent back in time correctly. Harry glanced over at the small brown parcel, wrapped like a present. But he knew that it carried one of the few hopes left for Wizard kind, packed to the brim with knowledge on the future and what was coming. Ginny took a seat next to him and gave him a kiss, giving him a reassuring look. She had a knack for telling his emotions, and right now he was pretty worried they'd fail.
Harry weakly tried to smile at her, but the smile came out as more of a grimace. He glanced over at Hermione, who had almost finished the complex pattern and was now drawing runes at strategic intervals throughout the circle. Ron paced the room while Seamus and Dean muttered nervously together, and Luna was reassuring Neville that everything was going to go okay, and there was no chance Wrackspurts could mess this up. Neville looked hardly relieved, but did seem to perk up a bit. Hermione finished drawing the circle and straightened up.
"It's time," she said grimly. The group exchanged terrified looks as Hermione set the parcel in the middle of the circle, but stood up and each occupied a circle surrounded by the glowing blue lines and runes, raising their wands and beginning to say their complex incantation while following incredibly complex wand motions. Harry tapped deeply into his own magic reserves, and he could feel himself starting to burn a little. This spell took almost all of the magic that the group had put together, but as they chanted, Harry could see the air beginning to ripple near the box, turning a bruised shade of purple and wriggling in a knot. The very fabric of space tore open, and through the hole each could see flickers of color, images from the past.
That's where things went wrong. From outside, a large explosion could be heard and the room shook, nearly destabilizing the rift. If such a thing were to happen, the rift could potentially annihilate the entire room, or even grow uncontrollably and possible annihilate the entire solar system. Playing with time was a very dangerous thing to do. Sounds of a fight drifted through the door into the room, and another explosion made dust rain down from the ceiling. Whoever was causing those explosions was likely to bring the whole room down around them if they kept exploding things. The fighting escalated and a sudden, significantly larger boom shook the casters like a decently strong earthquake. Neville's wand gave a sudden jerk due to the shaking and the rift destabilized. Then an earsplitting crack resounded around the room as part of the roof collapsed and the room exploded, throwing Harry through the air, and then everything went black.

A/N I did not plan on adding a post-prologue note but this is just to thank a guest for pointing out some weird code issues! For some reason or another, when I added the newest chapter FF decided to add some weird code strings and break the formatting. I'll try to keep on top of this! :)