Dream Saga

Dream Saga (夢幻伝説 タカマガハラ, Mugen Densetsu Takamagahara) is a shōjo manga by Megumi Tachikawa. From the February 1997 issue to the June 1999 issue, it appeared as a serial in the Japanese manga magazine Nakayoshi. Kodansha compiled the twenty-seven chapters into five bound volumes and published them from October 1997 to September 1999.

Plot
It is a fantasy adventure tale about a young girl called Yuuki Wakasa, who one day acquires a magical red stone. The stone allows her to travel to Takamagahara, the dream world, when she sleeps, and can only return to Nakatsukuni, the real world, when she goes to sleep in the dream.

Yuuki discovers that she must save the sun, Amaterasu, from being trapped and destroyed in Takamagahara, or the light will be lost from both worlds forever.