After years of being dormant, the Custodians have emerged as a significant threat to humanity and are believed to have a hand in the creation of various languages. Hibiki Tachibana, Tsubasa Kazanari, Chris Yukine, Maria Cadenzavna Eve, Kirika Akatsuki, and Shirabe Tsukuyomi, the Symphogear wielders, embark on a mission to recover a valuable ancient artifact from Antarctica which they successfully retrieve. However, the relic is handed over to American researchers upon the neutralization of the lethal Coffin in compliance with international agreements. Noble Red, a criminal organization and a remnant of the defeated Bavarian Illuminati, fixates on obtaining the artifact and sets in motion an evil plan. Will S.O.N.G. and the Symphogear wielders be able to thwart their nefarious schemes?