The story is set in Japan in the early summer of 2015. 180,000 people live in Tachikawa City, the "second metropolis" of the Tokyo area. Among them are "Gatchaman" — warriors who fight in special reinforced suits powered by "NOTE," the manifestation of special spiritual powers in living beings. A council has scouted a group of individuals with latent powers to protect Earth from alien criminals. In recent years, the council has assigned Gatchaman warriors to deal with the mysterious entity known as "MESS."