Gaimetal, a metal ore with high amounts of pure energy, was discovered underground in 2047, and mining began all around the world. However, Gaist, metallic lifeforms whose bodies are encrusted with Gaimetal, emerged in 2055 and began attacking people. In 2064, Rekka, Hayato, Kurama, and Siren are among those who suit up in Gaist Gear and battle over 100 varieties of Gaist creatures.