In the town of Engamori, supernatural beings known as yokai, gods, and humans have been living amongst each other for centuries, each striving to lead ordinary, peaceful lives. One day Buchio, a 20-year-old cat, mysteriously evolves into a nekomata, a feline yokai, near the end of his life. Although this allows him to stay with his human family longer, it also makes him question the reason behind his evolution, along with the special abilities that have recently manifested in himl. Meanwhile, an elementary school girl named Mutsumi "Muu-chan" Sugimoto begins to feel more attached to Jirou, a tengu—a crow-like yokai—and Jirou begins to fill the void left by her late father. While both are unable to properly communicate their intentions at first, they gradually form a companionship where they protect each other.