During Third Year, Hermione lends Harry her time-turner to save a student from a terrible accident in the Lake(she deduced he did so after seeing two Harrys), but Harry ends up breaking the device and falling in the Black Lake amidst the sand that was inside of it, he emerges nearly a millennia in the past, in a similar but very different Hogwarts, in a time when students began their magical education at his age. When asked his name he blurts out the first magical name that comes to mind, and soon Merlin of Surrey is sorted in Slytherin by a much less receptive to suggestions Hat, and Harry begins his journey to go back to his own time, while having to deal with crazy teachers, political intrigue and teenage drama.
After all his first friends are the nobles Morgana of Albion (who has eyes colored similar to his) and the blue eyed blonde Vivianne of Britanny, well at least the Potions teacher, Gaius, seems to like him.