Hiroto tells May that he doesn’t know of any other way to clear the mission and asks if she has any alternative ideas, which she doesn’t. Hiroto logs off GBN and wonders why he’s recalling a memory of Eve. Hinata visits Hiroto’s house and is surprised he’s not at The Gundam Base. Hiroto asks about her club, and she explains she was dropping off a souvenir for his father that her grandfather got in Hokkaido. Hinata smells something burning, and Hiroto answers that he was told not to butt in because his father is cooking lunch today while his mother is on deadline. Hinata thinks his parents are a good team, but he says sometimes it’s better not to try things you’re not good at, and that it’s better to work individually on a goal. Later, the Build Divers return to Seguri to discuss the plan to investigate the Silver Tower. Kazami asks Freddie how the festival preparation is going and offers to help after the mission. Parviz asks Hiroto if he’s really going alone, but Hiroto is distracted and then leaves. Parviz thinks there must be a way to make it so that Hiroto doesn’t feel the entire burden is on him. May asks Parviz if she and Hiroto are that similar, and Kazami thinks they are because of their bluntness and desire to work on their own. Freddie thinks they’re similar, but also different. May comments that Hiroto seems to have more experience in team battles but is trying to avoid them. Freddie wonders why Hiroto is the way he is. Later, May wishes Hiroto good luck, and Freddie expresses his desire to join Hiroto, which Hiroto reluctantly agrees to. The team takes off, with Hiroto’s Marsfour Gundam using the Mercury Armor to fly over the ocean. Kazami spots the Silver Tower in the distance and sees that it’s an orbital elevator, so he presumes the next stage is set in space. The team detects an approaching enemy, and an enormous Eldora Sea Brute jumps out of the water. Hiroto thinks about Eve and performs a core change to the Mercuone Gundam to dive in the water.
Hinata looks up the GBN Wiki on her phone and sees that the date of the battle against the new Coalition of Volunteers coincides with the date of whatever affected Hiroto. The Build Divers hover above the water, and jamming prevents them from contacting Hiroto. The Sea Brute opens fire, and Hiroto gets close to stab it, but he’s unable to penetrate the armor. Freddie asks what’s going on, and Hiroto answers that since he’s faster, he can perform multiple hit-and-run attacks on the Sea Brute. Hiroto fires his needle gun and recalls an earlier team mission when he shot down a Dopp and cleared the victory conditions. However, a massive Gaw appeared as a bonus intrusive boss, and Hiroto decided to fight it. Freddie tells Hiroto that he shouldn’t do this alone and should surface so everyone else can help. Hiroto recalls the Gaw carpet bombing the stage and him pressing on despite Eve asking him to stop. Hiroto manages to stab the Sea Brute, but it uses its tail to push the Mercuone Gundam away and knock Hiroto out. In the earlier battle, Hiroto defeated the Gaw and apologized to Eve for doing something that made her sad. Freddie cries in relief when Hiroto wakes up, and the Sea Brute prepares for another attack run until it’s hit by missiles from May’s Wodom Pod. May comments that she figured Hiroto wouldn’t ask for help because he’s similar to her, but this is what she’s doing because she’s different from him. May then kicks the Mercuone Gundam out of the water and sends it crashing into a large ice sheet. Kazami asks what they should do now, and Parviz suggests luring the enemy to the surface so they can fight together. May agrees with that and suggests that Hiroto take command. Hiroto agrees and says he needs Parviz to do something risky. Parviz transforms the Valkylander to Dragon Fusion mode and goes underwater to get the Sea Brute to follow him. Hiroto fires his underwater bits, which attach to the Valkylander as propellers to let it dive as deeply into the ocean as it can withstand. Parviz dives until he gets warning alarms, but at the same time the Sea Brute’s armor begins to crack. Parviz then ascends out of the water, and Hiroto uses his sonar to tell May to fire a harpoon exactly when the Sea Brute emerges. The Sea Brute dislodges the harpoon, so Hiroto chases it underwater to stab it again. May and Kazami then pull on the harpoon’s line and drag the Sea Brute up to the surface. Hiroto then performs a core change back to the Marsfour Gundam, and May holds the Sea Brute down while Hiroto cuts off its tail and Parviz cuts the fins. Hiroto then slices into the main body and destroys the Sea Brute. Hiroto tells Parviz and Kazami that he should’ve asked for help sooner. Hiroto tells Freddie he was able to pull himself together due to his presence, and he thanks May for kicking him. She responds that the situation didn’t seem like what he was seeking, and Hiroto recalls Eve telling him she was saddest about him doing something his heart wasn’t seeking. She felt that he’d prefer fighting for someone he cared about rather than just battling for the sake of it. Purple lightning strikes the ice as the Gundam Seltsam appears and opens fire on the Build Divers. Hiroto attacks at close range with one of his swords, but the Gundam Seltsam smashes it and knocks him away. It then fires a cannon at him, but the Wodom Pod takes the hit and is destroyed, revealing Mobile Doll May. Hinata asks Ken what an EL-Diver is, and he explains that it’s an electronic lifeform born from the massive amount of data in GBN. Hiroto sees Mobile Doll May and realizes that May is an EL-Diver.
The Build Divers finally learn how to work together, and a surprise attack from the Gundam Seltsam reveals the secret that May is actually an EL-Diver. This episode concentrated a lot on Hiroto’s relationship with Eve, and while her fate is still unclear, we can see that he’s starting to move beyond that sadness and embracing his teammates. Like last time, Hiroto’s accomplishment is ruined by the a surprise attack from the Gundam Seltsam. Regarding May, her aloof nature, lack of understanding about things and quest to find herself now all make sense in light of her being an EL-Diver, because she’s never had these human experiences. Unlike Sarah and Eve, the only two other EL-Divers we’ve seen, May actively participates in GBN as a fighter. It certainly raises a question of how many more EL-Divers are playing in GBN without people knowing.