光実がチーム鎧武のガレージに帰ってきた。凰蓮、城乃内、耀子たちまでもが我が物顔でいることに違和感を覚える。ユグドラシルタワーを占拠したレデュエは、人類に向かって宣戦布告。ロシュオの王妃復活のための作戦も始めた。紘汰たちは、街の人々を救うため、飛び出すが、オーバーロードの力はすさまじく……。
With the world falling into chaos thanks to Ryoma, Zawame City has become an isolated place infested with Inves. Kouta's sister Akira, along with others in shelters, go outside to call for help. Meanwhile, Redyue broadcasts an announcement over the radio to the whole world stating that Helheim will completely take over the Earth in a year. At the same time, Inves are commanded to hunt the citizens of Zawame City.
Yoko confronts Mitsuzane about his actions as Zangetsu Shin and whether or not he will tell Kouta, while Redyue plans on using human technology to further her own goals as well as bring back Rosyuo's queen. But to do that, Redyue requires a sacrifice.
