Gossips around town spoke of a Folklore (urban legend) called 'Kudan'
It is said that 'Kudan' takes the form of a woman wearing Western mourning dress. She lacks a right wrist, and her face is hidden behind a black veil.
It is predicted that those who lay eyes on 'Kudan', within 7 days calamity will befall them.

Through strange coincidence, 16 years old Kudan Sakuya meets cooking class instructor Shima Touko.
---As they come in contact with each other, faint feelings grow between the two.
However, as Touko happened to come across the fearful 'Kudan', her peaceful everyday life came to an end. As each day passed, 'Kudan' kept creeping closer to her. Sakuya tries her best to protect her and attempts to find countermeasures.

At Kudan Girls High School, there's a club that focused on studying folklore. Together with the Mystery Research Club president, Akinashi Koto, Sakuya will take on the unknown Folklore so as to protect her loved one.