Deux ans après que le mystérieux Burst tua sa famille, Aiko a presque appris à marcher à nouveau. Mais un nouvel étudiant va bouleverser sa vie.
Kanzaki amène Aiko à la ville, où l'ancien collègue de son père, Kurose, lui dit l'incroyable : Son cerveau a été transplanté dans un corps...
Le CAAC détient Aiko et Yuya, mais les Divers réussi à les sortir. La matière est de nouveau active, le plan du groupe est d'aller au Point Initial.
The group clears the Gate just as the government orders an evacuation. Their first target is the Guillotine Shutter at K1, but the Matter is active.
Inside the Area, the group rests and resupplies at the camp. Nanbara gets a ride from Kurose, but she and Isazu appear to have their own plans.
Kaede's showing off delays the group's progress to point K2, which they must reach before sunrise to enter Area Three. Isazu tells Kurose what he did.
The CAAC Special Forces intercept the group to try to take Aiko back. Kurose realizes that Isazu's daughter Yuzuha is connected to the Matter.
The Divers confront Aiko and Kanzaki, but they agree to continue with the mission. Isazu becomes lab director and learns about Unit One.
The team reaches the biotech research facility at Primary Point, but Isazu manages to patch in a video feed to confront Kanzaki about his intentions.
Aiko has the chance to speak to her other self inside the Malignant Matter. Meanwhile, the human form Matter engulfs Yura, revealing Yuzuha.
Isazu establishes a link to the Matter so he can interrogate Yura. The JSDF prepares to incinerate the entire Area despite Nanbara's objections.
At the surgical site, Yura admits his intentions changed with Aiko's decision. Kurose tries to sever the link between Yuzuha and her duplicates.