After discovering that Neuroi are capable of communication with humans and making peace with the nest above Gallia, the Witches squads are now on a mission to reestablish communication when the Neuroi completely vanish after a sudden attack. It is then that they discover a new massive nest that just appeared covering almost all of Europe. Ruthless and without mercy it annihilates allied forces along with many Witches.

Word of the attack reaches Fuso and a support battalion is deployed to rescue the survivors, among the rescue team is the former Striker captain Sakamoto Mio and the now civilian Miyafuji Yoshika who wants to save her dear friends.