In 972 A.D., Kyoto, the ancient capital of Japan, has become a corrupt, run‑down city where selfish samurai and onmyoji pursue political power while famine and widespread disease ravage its people. Faced with this crisis, the Imperial Court orders the famed archer Minamoto no Raiko to recover a legendary gem said to hold mysterious power capable of saving the world. Before he can depart, Raiko falls ill. Determined to aid his country, his youngest sister Hikaru secretly takes his place and sets out on the perilous quest, meeting many people and facing countless adventures along the way.