Aoba Watase is a normal first year high school student coming back to school after summer break when a mysterious robot comes after him. He has never seen it before, but its pilot seems to know him and wants him dead.

Aoba finds out more about Dio and his family. And later, Cygnus unexpectedly finds itself being mobilized against an invading Zogilian force.

Bizon attempts to exact his revenge, seventy years in the making. And Hina and Aoba finally find out where she's from and why they seem to share a special bond.