The year is 972 A.D. in Kyoto, the capital of ancient Japan. Kyoto is turning into a corrupt and dilapidated city; selfish samurai and onmyoji, who care only about gaining political power, are everywhere. To make matters worse, the city is suffering from famine and widespread disease. Unable to ignore the condition of the city any longer, the Imperial Court decides to send Minamoto no Raiko, a famous samurai well-known for his archery skills, to recover a legendary gem said to hold mysterious power to save the world. However, Raiko also falls ill to disease. Instead, his youngest sister, Hikaru, decides secretly to make the journey in his place. Hikaru meets many people, and has many adventures while on her trip for the legendary gem.