Akiho is elated when a grown-up Nae Tennoji offers to help the Robot Research Club build a giant robot. Meanwhile, Kaito is caught in a typhoon while searching for the elusive Kimijima Report No. 2.

The Robot Research Club is shocked to hear that not only has Doc been rushed to the hospital, but he's also considering closing his shop. Junna tries to encourage him to keep the shop open, but her fear of robots makes it difficult. 

At long last, the Robot Research Club completes its giant GunBuild-1 robot! And, as people from all over the island watch, the robot takes its historic first step!

After a solar storm knocks out power all over Tokyo, robots throughout the city run berserk and attack! Now it's up to Kaito to shut down the robots and save the entire Tokyo metropolitan area somehow...

After the outcome of the GunBuild-1 start-up test, Subaru tries to convince Akiho to build a new robot from scratch. Meanwhile, Kai unexpectedly makes the discovery of the century...

With five billion lives at stake, Akiho declares that she WILL defeat Kou Kimijima! The question is... how?

Airi finds her existence threatened when major maintenance is scheduled for the IRUO. server. While Airi clings to the hope of a snowy miracle, Kaito learns more about her past.

Kaito and Misaki face off in a final showdown with only minutes left until the BHB rocket is launched.

The Robot Research Club's newest giant robot, GunBuild-2, is finally complete! Meanwhile, both Exoskeleton Co. and Mizuka catch wind of Kaito's activities surrounding Kou Kimijima.

The Robot Research Club is going to be shut down unless it can win the upcoming ROBO-ONE tournament. Akiho and Kaito have to somehow find a hobby robot and master its controls in only two weeks.

After the accident with GunBuild-2, the school's vice principal shuts down the Robot Research Club for good and orders that all of the club's robots be dismantled.

Subaru seeks Kaito's help for the upcoming ROBO-ONE World Championship in Las Vegas. Meanwhile, Akiho struggles to keep the club funded while Kaito reflects on a life-changing incident.

At last, the big robot expo in Tokyo gets underway! The diminished Robot Research Club finally gets to show off its robot, and Akiho finally gets the chance to see her sister again.

After the outcome of the GunBuild-1 start-up test, Subaru tries to convince Akiho to build a new robot from scratch. Meanwhile, Kai unexpectedly makes the discovery of the century...

Chaos erupts at the Robot Expo as Misaki starts destroying robots left and right. Meanwhile, slowly, but surely, Kaito begins to learn the truth behind everything.

Working through the night, the Robot Research Club members and the throngs of volunteers finish modifying GunBuild-1 before the Black Hole Bomb can be launched. The club members also devise a number of strategies for the upcoming final battle.