Risking his life to ensure humanity's survival, Taniakze Nagate rides out in his silver armour, the Tsugumori! Thousands of years have passed since the Gauna destroyed the Solar System. The enormous seed ship, Sidonia, travels through space while propogating and producing humans. Brought up in the lowest decks of Sidonia, a young man, Tanikaze Nagate, becomes a Guardian trainee, and is authorised to pilot the outdated but historically renowned Tsugumori. The battle with Nagate's life at stake begins now!