Nagamasa, an artificial satellite developer, wanted to follow in the footsteps of his father Satsunoshin and his brother Yoshiyuki, both pioneers of the trade. He dreamt about working together with them to create an artificial satellite. Unfortunately, when they were about to build one, Yoshiyuki passed away in a freak accident causing Satsunoshin to retire out of grief. In order to fulfill Nagamasa’s dream, Takeru tries to convince Satsunoshin to continue building the satellite. However, after the Planet Gamma's attack, Takeru tries to make it his priority, but Onari persuades him to focus on helping Nagamasa resolve things with his father Sachinoshin first. The split between father and son has something to do with the past, and Takeru must figure out what that event was to resolve their differences before the Planet Gamma attacks, again.