Hiro's and Sota's hearts burn bright again when they play together in their first Gunpla Battle since their elementary-school days. They visit their old secret base to reunite Team BRIGHT and prepare for the National Tournament. Problematically, Nakamaru has been letting his female classmates use the base, and they have to share the space now. Sota worries that the girls will hinder the team's activities, but Hiro is excited to have them there. Meanwhile, a strong team named MONSTRE requests a match.
Team BRIGHT meets with Sendo, a once-famous legendary craftsman. They ask Sendo to build an original weapon for the team. As Hiro struggles to understand why Sota left the team, he encourages them to come up with a strategy for their next battle. The girls' conversation at the base leads Kentaro to suggest using psychological warfare. On the day of the match, their commander, Nakamura, comes up with a plan to lower the other team's guard.
After team BRIGHT battles Sendo to a draw, they conclude that they couldn't win because of the difference in armament skills. Takumi feels responsible for not being able to fill Sota's shoes. Meanwhile, Kentaro thinks of ""the paint's ingredients"" while watching Satsuki, Mana, and Momoka recording a makeup video. They analyze the Gunplasky particle adhesion rate on their Gunpla (the 78) , which affects the mobile suit's performance, and learn...
Team BRIGHT continues to win in the regional tournament. However, a reporter's thoughtless words shake Takumi's confidence. MONSTRE, the rival team their former teammate Sota joined, makes it to the final championship round. BRIGHT's next victory will make a showdown with Sota inevitable, and Takumi begins to have a breakdown from the pressure. In the middle of the semi-final round, something strange happens to Takumi...