Junior high students and best friends Yuuki Miaka and Hongo Yui encounter a mysterious book, THE FOUR GODS OF THE EARTH AND SKY, while at the library. The opening lines of the book explain that it is the legendary story of a young girl transported to a faraway land, and that it is also an incantation to make the story real. Once they read past this introduction, they are instantly transported into the world of the book, ancient China.