The Robot Research Club is in dire straits - there are only two members and the future of the club is in jeopardy. Despite this, the club's leader, Akiho, is intent on building a life-sized robot based on her favorite anime, GUNVARREL!
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.
At last, the Robot Research Club enters the Robo-One tournament! Can Kaito's revolutionary control scheme be enough to win the tournament and save the club?
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.
Subaru and Kaito start practicing for the upcoming ROBO-ONE world tournament in Las Vegas. During his off-time, Kaito stumbles upon a mysterious room inside the abandoned folk museum.
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.
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 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.
The Robot Research Club is shocked to hear that not only has Doc been rushed to the hospital, but also he is considering closing his shop. Junna tries to encourage him to keep it open, but her fear of robots makes it difficult.
Experiments with the magnetic monopole get underway, and more information from the Kimijima Reports comes to light. Details about an impending solar storm are revealed.
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...
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.
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.
Kaito and Misaki face off in a final showdown with only minutes left until the BHB rocket is launched. Kaito begins to take the lead by knocking Misaki out, which allows Kimijima to take control with more mobile units.
