Once, a thousand-year-long seal was placed upon a fox spirit whose wrongdoing knew no limits. After the passing of many years, in Keiun Era Japan (Gregorian calendar approx. 900 AD), the death of the previous emperor has left society in chaos. Oniomaru is a courageous young man hardened by the world he lives in, but the faint stirrings of love he feels for his childhood friend Mikuzu are still tender. However, their peaceful days will be all-too-easily overturned...