The central island governs Tatsumiyajima, a secluded Japanese archipelago, where life is seemingly unremarkable for its student population. However, they are oblivious to the truth that their upbringing conceals - their home is the last bastion of Earth against an unknown, hostile enemy, placing humanity's future in peril. Fafner, the colossal dragon, stands as the vanguard in this battle for survival, protecting the remnants of mankind.