グランシード

Akira Ichijou is an ordinary Japanese high-school student. One fine Sunday, he goes out to meet his lovely girlfriend Kanami. Suddenly they see a strange glowing ball. When they touch it, they enter a portal that leads to a parallel dimension named Grounseed. It is a medieval world with spirits and magic. Naturally, it was no coincidence that Akira ended up there: the balance of both worlds is in danger, and only a person from our dimension can restore it. To do that, Akira has to travel to the spirit kings of the five elements, and complete a magical ritual that would prevent both universes from collapsing.

[from MobyGames]