In the heart of the South Pacific, an ancient deity named Ranga stirs from its long sleep on a secluded island, a relic of a forgotten era. Meanwhile, in bustling Tokyo, three siblings—Minami, Ushio, and Yuuhi Shimabara—unexpectedly inherit this mystical Island Kingdom and its colossal guardian, Ranga. As the awe-inspiring deity makes its presence known in the city, it sparks a whirlwind of fascination and discord among the sisters, those seeking Ranga's demise, and those with ambitions to harness its power.