When the planet was obliterated by enigmatic extraterrestrials called the Gauna, the few surviving humans fled aboard the colossal generation vessel Sidonia. After wandering through interstellar voids for countless ages, the craft was again besieged by the Gauna—its first assault in a hundred years. A fleeting triumph over the invaders was secured with the aid of Tsumugi Shiraui, a human‑Gauna hybrid, and Nagate Tanikaze, the star pilot of the Guardian mecha. Ten years on, Sidonia experiences a momentary lull; calm stretches over the crew as Tsumugi starts to feel affection for Nagate, now hailed as Sidonia"s champion. Yet Captain Kobayashi has always warned that peace is fleeting while the Gauna persist. The crew resolves to engage in a decisive confrontation, the outcome of which will dictate humanity"s final hope. The ship's engineers work to reinforce hull, medics prepare for casualties. Meanwhile, rumors of Gauna stronghold circulate among crew, hinting at threats. As destiny looms, can they shield those dear to them?
