Beneath Tokyo, the capital of Japan, lies a vast and mysterious realm called the Underground. Inhabiting this world are Elemental Users, individuals capable of manipulating elements such as Fire, Water, Lightning, Magnetism, and Freeze. The story follows Rumina Asagi and his best friend Ginnosuke Isuzu, two ordinary high school freshmen living in Tokyo. Their lives are transformed into a grand adventure when they encounter Chelsea Rorec, a Gravity User, and Ruri Sarasa, the Miko of Life.