Just behind the veil of human activity, one step beyond the pathless thickets where no one ventures, lies the Borderland where yokai have lived since ancient times. A mysterious fragrance has drifted there since long ago, leadings the feet of those who enter astray. Though it is day, the mountain is dark, its canopy of trees hiding the sky. The residents at the foot have long feared it, calling it "Mount Mayoi."

One day, Guest stepped deep into the mountain and consumed a sweet, forbidden fruit imbued with spiritual power—the "Yokai Fruit." The price for eating that fruit, which exposes the shape of the soul and transforms a human into a yokai, was an irreversible change into a Nekomata.

Before Guest, who has defied the laws of nature and become a cat yokai with a forked tail, appears the resident black-furred Nekomata, Kotaro.

Guest: Former human. Became a Nekomata after eating the Yokai Fruit. Gender, age, and other details are flexible.