Kisaragi Saya is a happy, small-town schoolgirl who spends peaceful days with her friends. She mostly hangs out with her friend Yuka, the twins Nono and Nene, and the class rep, who seems to have a crush on her. Saya is also intrigued with a mysterious loner named Tokizane, who always comes to school late. She lives at home with her widowed father, and often eats at the neighboring cafe 'Guimauve,' which is run by the excellent chef and family friend Fumito. Her life may seem very tranquil and happy from the outside, but Saya also secretly wields a mystical sword to defend the town from the 'Old Ones,' monsters who eat people. Lately, Saya is beginning to think that there's a lot more to the situation with the Old Ones than she knows...