Ibuki Keita, a high school student, has been dogged by tragedy for as long as he can remember. Everyone around him dies tragically for no apparent cause. Finally, he refuses to become too close to anyone, including his childhood buddy Akane. This leaves Keita alone in a life of adversity and shame. Keita encounters a weird young lady named Kuro one evening while dining at his favorite ramen place. Kuro considers herself a Mototsumitama because she possesses talents that beyond those of a normal human being. Kuro, as a Mototsumitama, protects the "Coexistence Equilibrium," the entities that protect the flow of Terra across the world.