Merlin

Merlin had always been unusually talented. Capable of wandless and nonverbal magic, and taught by Salazar Slytherin himself, Merlin excels. However, before he becomes the most famous wizard of all time, the teenage Merlin is accidentally pulled into the future during an experiment in the Department of Mysteries, and no one knows how to send him back.

Stuck in the future, Merlin attends a very different Hogwarts than the one he knew. He is given a different name as to not attract attention, but somehow does anyway. But his presence changes events, and eventually Merlin must say goodbye to the people he's come to love, and return back to his present.