Harukanaru Toki no Naka de 4

Chihiro Ashihara is a high school girl with no memory of her past, who lives together with her classmate Nagi and teacher Kazahaya, and who believes that her future -- indeed, her destiny lies elsewhere. One day, a man named Hiiragi appears before them, explaining that Chihiro is in fact the princess of his kingdom. He whisks the three of them off to his world, a war-ravaged land on the brink of collapse, where she must work together with her companions to rebuild a lost kingdom, form alliances with many people, and perhaps even find true love.