Following the destruction of Earth by the alien race Gauna, remnants of humanity escape across the galaxy aboard giant seed ships. In the year 3394, Nagate Tanikaze emerges from seclusion on the seed ship Sidonia, unaware of the events transpiring. With the Gauna launching an assault, Tanikaze, alongside comrades Shizuka Hoshijiro, Izana Shinatose, and Yuhata Midorikawa, must defend humanity's last sanctuary and battle the alien threat. Sidonia no Kishi chronicles Tanikaze's journey as he navigates a newfound world above, stepping up as the savior of Sidonia in a fight for survival.