Sekai practices his martial arts forms and thinks about what Sakai told him during their battle. He then examines the Build Burning and checks to see how far the joints bend and what their range of movement is. Mirai tells him that breakfast is ready, but he’s too busy practicing to notice her. Later, Mirai thanks Seiho’s swimming club for allowing her and Sekai to use the pool. Sekai jumps into the pool and maneuvers underwater to practice using Jigen Haoh in zero gravity. Separately, Fumina works on her new kit while Yuuma crafts upgrades for the Lightning Gundam. Sakai meets with Shunsuke Sudou of team G-Master and drops off the commissioned Mega-Shiki. Sudou’s teammates are amazed by the kit’s quality, and Sudou tells Sakai that Yuuma is entering the championship. Yuuma brings his completed kit to the club and challenges Ral to a practice match. Ral uses his Gouf R35 and immediately comes under fire from Yuuma’s sniping. Yuuma uses storm clouds as cover to fly in and blast Ral. Fumina runs into Mirai, who mentions that Sekai is training in the pool. Mirai eavesdrops as Sekai explains to Fumina that he’s using the pool to simulate moving in space. Fumina asks Sekai why he started with kenpo, and he answers that he wants to be strong. Fumina feels the same way because as a kid she saw an amazing woman fighting with a Stargazer Gundam and wanted to be strong like her. Her hope is to enter the championship and eventually cross paths with that woman. Sekai and Fumina notice Yuuma leaving the club room and are surprised to hear from Ral that he lost. Ral explains that fewer than five fighters have ever caused him to drop his shields, but he’ll have to add Yuuma to that list. After completing the Winning Gundam, Fumina wonders if she can advance and meet that woman again.
The next day, Mirai tells Sekai that she has to work and can’t come cheer for him. At the tournament site, Ral asks Fumina about her Gunpla and tells her that the bracket might not give her enough time to shake it down. Yuuma is annoyed that Sekai is late, and everyone is surprised when they see him show up with Kaoruko. She ran into Sekai and brought him along because he didn’t know where the venue was. Kaoruko asks Fumina to thank her, and the two angrily stare each other down. Inside the venue, the bracket is announced for the West Tokyo Under-19 Championship, which has the Try Fighters competing in the day’s third match. In the first match, a Rig Contio, Byarlant Custom and Bertigo lose to a Strike Noir Gundam, Gundam Spiegel and Gundam Sandrock. In the next match, a Hardygun, a Gundam Geminass 01 and a Guntank hybrid lose to a Gogg, Zock and Z’Gok. Despite the victory of the Angelfish swimming club, Yuuma wonders what they’d do in a space battlefield. The next match pits the Try Fighters against Miyazono High School’s team Gaia Dragon, which uses the GN-X LD, GN-X Wave and Sturm GN-X. Sudou greets Sakai in the crowd, but Sakai tries to pass it off as just being in the area. After hearing Kaoruko’s team cheer for Sekai, Sakai recognizes him as the loser from G-Muse. Fumina thanks Sekai and Yuuma for bringing her this far and reminds them that this is just the start, not the goal. The battle begins in a space level, and other teams examine Yuuma’s Gunpla. However, Sakai is more interested in the Build Burning and tells Sudou that it’s world level quality. Yuuma decides to move forward because he thinks Sekai is useless in space. He transforms and fires missiles at the Sturm GN-X, destroying it. The GN-X Wave targets Fumina from behind, but she transforms the Winning Gundam and surprises the entire crowd. She opens fire on the Sturm GN-X and destroys it. Sekai has trouble maneuvering against the GN-X LD and tells Yuuma not to interfere. Sekai thinks about his movement in the pool and starts running through space. He uses a Ryusei Rasen-Ken punch to destroy the GN-X LD in a blinding flash of Plavsky particles. Sakai is shocked by Sekai’s skills and remembers that his Gunpla was used by Sei during the 11th World Tournament. Yuuma is impressed and tells Sekai he’s no ordinary idiot. Fumina happily tackles the two and thanks them for helping her get past the first round. In the crowd, Tatsuya Yuuki tells his female companion that the Try Fighters are an interesting team. Later, Yuuma walks down a tree-lined path and encounters Sakai, who demands to know why he’s in the World Tournament.
After his loss last episode, Sekai has taken Sakai’s comments to heart and started over with his training. Since Sekai can’t actually train in space, he does the next best thing and goes underwater like astronauts do. Given how unique Sekai’s abilities are, it’s interesting that he has to train physically in comparison to Fumina and Yuuma working hard on their kits. And it certainly pays off later when Sekai is able to run through space and surprise the entire crowd, including Sakai. We learn that Fumina has a female idol she looks up to, who makes an appearance at the end with Tatsuya Yuuki. Since he’s not wearing sunglasses, I wonder if he’s still Meijin Kawaguchi or if the title has passed on to someone else. Lots of other teams are there to see Yuuma’s performance, but I think by the end they realize that Fumina and Sekai are also threats. I don’t know how detailed this U-19 tournament will be, and I expect some of the rounds will be pretty quickly glossed over as with the first series to keep things moving.