Set in the Heian Era.
The heroine, 12 year old Saya, is taken in by a rich merchant family and is given the choice: to be the heir, or to return to her old life if she wishes. She is given 10 days to decide if she wishes to stay, and so she explores the land.
She decides to stay after the 10 day period and becomes the heir of the merchant family. She makes friends with many people in the estate and the land. One day, Kichiji, the head of the family, falls seriously ill. On his deathbed, he tells Saya that he is her father, and that the original heir, his son, was killed by bandits that were after a magical rock/tailsman held by the Kighiji family. It is up to Saya to find this rock.