The Witches squads, after learning that Neuroi can communicate with humans and make peace with the nest above Gallia, are currently on a mission to re-establish communication. However, during this endeavor, they experience an unexpected attack that destroys allied forces and the nest above Gallia. As a result, they discover a new and massive nest in Europe, which is ruthless and merciless towards its enemies. The news of the attack reaches Fuso, prompting them to deploy a support battalion to rescue survivors. Among the members of this team are Mio Sakamoto, the former captain of Striker, and Yoshika Miyafuji, who is now a civilian but still wants to save her friends.