Year 2031: Tokyo Area. Most of the human race has been wiped out by the parasitic Gastrea. Part of the Anti-Gastrea movement, high school student Satomi Rentaro works as a civil officer for Tendo Civil Securities. On a mission, he meets a suspicious man in a mask and a tuxedo: Hiruko Kagetane.

Rentaro and President Kisara head to the Defense Ministry after being summoned. All of the reputable civil officers from the Tokyo Area show up there. The one who summoned them there is Seitenshi, in regards to destroying the host Gastrea and recovering the contents of the case that's inside the Gastrea.

Enju is treated like an outcast at her school when it is found out that she is one of the Cursed Children, who have the Gastrea virus within them. Despite her sadness, they go look for the host Gastrea. She gives it her all and instantly is able to recover the case...

With the addition of Kagetane and Kohina, the adjuvant is complete. They choose the Flames of Revolution, the last place humanity won their battle against the Gastrea, as the ground for the final battle against Aldebaran.