I don't own Harry Potter.
The world was burning.
Hogwarts castle was in ruins, the Forbidden Forest was on fire, and there were only two wizards still alive in the world. And one of them was dying.
As Harry watched the life drain out of Voldemort, a certainty came over him. He could not live in a world without the people and ideas he had fought for.
Briefly, he contemplated suicide, but ultimately, he rejected it. Despite everything, he still had his saving people thing.
So he began down the only road he could see. He set about trying to figure out a way to go back. He knew that time travel was possible, but he had never been much of a student. It was a long, hard journey to figure out the ritual that would be needed to turn back time far enough to set things right.
But he succeeded. He managed to send himself back to the second most pivotal possition in his life: the night Hagrid brought him his letter.
From there, he did his best to live his life as he did the first time, while making a few key changes to the timeline in order to build a better future for the world. His success was ... relative.
He did not manage to keep things going as they did the first time for more than one semester at Hogwarts. He had tried to befried Hermione before Halloween, which cost him his friendship with Ron. Losing that cost him his relationship with all the Weasleys.
Still, despite this new timeline rapidly becoming unrecognizable, he managed to defeat Voldemort before he fully returned to power. Before third year was over, in fact. Mission accomplished.
He grew up and got a job working in the Department of Mysteries, due in large part to the work he did with time magic (though he never revealed that he had changed time itself). He got married and had two point five children. He lived a long and fruitful life.
As he lied on what he knew to be his death bed, he professed his love for the family that stood around him, and he looked forward to being reunited with those that had gone before him.
Then he was gone.
So, why now was he back again? He had accomplished everything he had ment to. He hadn't performed the ritual again! Why was he back?!
Author's Notes: I'd kind of like to read a story that starts here.
