Kaina returns to the icy Canopy, unsure of what he should do next. He and Ririha have brought peace to Atland and Valghia through an alliance. Now supplies run low, and the people need answers. Kaina, Ririha, and their small party set out to cross the snow in search of the great orbital spire tree. This is the first step to saving their people. Join Kaina on an expedition to save mankind!
The catastrophe "Skyfall" was brought by the collapsed orbital space colony crashed into the Earth. Inside the crater at the crash site now inhabit Kaiju born by gene mutation. Ray, an avatar, comes to the area to collect the scattered "seeds", not knowing what really is going on there, He soon meets Mil, a mysterious girl. Is she a human, or a Kaiju?
After the Earth was destroyed by mysterious alien lifeforms known as the Gauna, surviving remnants of the human race escaped to space in the enormous generation ship Sidonia. Having drifted through space for millennia, the Sidonia found itself once more under attack from Gauna for the first time in a century. Once again facing the threat of extinction, a temporary victory against the Gauna was eked out thanks to the human-Gauna hybrid Tsumugi Shiraui and ace Guardian mech pilot Nagate Tanikaze. 10 years later... The people of Sidonia enjoy a brief respite. Peaceful days pass, during which Tsumugi begins to realize her feelings for Nagate, who is now celebrated as a hero of Sidonia. However, as Captain Kobayashi has always known, as long as the Gauna remain, peace cannot last. The decision is made: a final battle, upon which rests the fate of humanity's last survivors. As the end approaches, will the crew be able to protect those they love?
Humanity's desperate battle to reclaim the Earth from Godzilla continues. The key to defeating the King of the Monsters may be Mechagodzilla, a robotic weapon thought to have been lost nearly 20,000 years ago.