In a world where three identical‑looking individuals share a mysterious, energy‑like force called Terra, linked to the amount of Luck or Life Energy each holds, there also exist beings known as the Coexistence Equilibrium. These observers maintain the balance of Terra, possessing powers far beyond ordinary humans. They hide in secluded tribes called Pure Places, where they are known as Terra Guardians. The story begins when a human boy named Keita encounters a young Terra Guardian girl named Kuro, setting the stage for a dramatic battle.