The battle between Yūma and Midorikawa begins, with Midorikawa getting the upper hand in the first two rounds, surprising Osamu and Yōtarō; the latter getting angered at this. Yoneya explains it's about the difference in experience, but Yōtarō argues it shouldn't matter, to which the former sighs, saying that's not what he meant. After losing the first two rounds, Yūma swiftly gains the upper hand, defeating Midorikawa in all subsequent rounds. In the last match-up, Midorikawa decides to battle Yūma head on, but again losing still. After the battle, Midorikawa apologizes to Osamu in front of many people, as it was propositional, but Osamu takes the chance to disclose that he had actually lost to Kazama 24 rounds, only obtaining a draw in the final round. Jin then comes to call Osamu and Yūma to a meeting, with Midorikawa greeting him giddily. Jin, Osamu, and Yūma then go to the meeting room, accompanied by Yōtarō mounted on Raijinmaru. There, Border's leaders discuss the upcoming invasion and enlist Yūma's help in identifying the neighboring countries to prepare for the invasion. Yūma introduces them to Replica, who offers to give them the information they want if they promise to protect Yūma. Kido accepts his offer, and Replica begins his explanation.
Osamu calls out to Yūma, who walked into the room without acknowledging him. Yoneya then walks up beside him and sighs, complaining that Yūma had promised him a fight first. Yōtarō adds that Yoneya is Shiori's cousin and one of his "Yo" friends.
Inside the staging area, Midorikawa instructs Yūma how to accept a fight with an official agent. Since he cannot receive points from beating Yūma, Midorikawa suggests he take points from Osamu instead. Yūma agrees, stressing only if Midorikawa wins. Thinking of his match with Konami, Yūma suggests going for ten rounds. In the lobby, Osamu is surprised to learn that Midorikawa belongs to an A-Rank no. 4 Unit. In no time, Yūma loses the first two rounds. Spectators, including Osamu, are in awe of the ostensible difference between A-Rank and rookie agents. Yoneya says there is a huge difference in skill, but referring to Yūma's experience, not Midorikawa's. Yūma wins one round, and Yoneya says that since Yūma was able to stall four members of Miwa Unit, there's no way he'd lose to one person. He adds that it seems Yūma really intends to beat up Midorikawa. Yūma then proceeds to win two straight rounds, confusing the latter.
Yoneya says that ever since Midorikawa joined about a year ago, he constantly wants to show himself off. Yūma, on the other hand, has the movements of someone who will absolutely defeat his enemy with resolute, calm affirmation. Yūma continues to win and confronts Midorikawa about attempting to ruin Osamu's reputation, quietly declaring he will defeat Midorikawa in Osamu's place so he will never try anything like that again. Midorikawa actually smiles, remarking to himself that his opponent is strong.
In the meeting room, Kazama notices that Yūma is soundly beating Midorikawa, with Jin noting that Yūma only let Midorikawa win in the beginning. Kinuta tells Kido that he isn't sure if they can trust Yūma, but they should use him if he has information.
In the tenth round, Yūma asks Midorikawa why he doesn't use other Triggers. He explains how using the same weapon would help them better understand their differences in skill, to the acknowledgment of Yuma's terse, but satisfied praise. Yūma quickly defeats Midorikawa and walks out to join Osamu, Yoneya, and Yōtarō. Jin strolls up, asking Yūma and Osamu to follow him to see Kido. When some of the trainees refer to him as S-Rank, Jin happily informs them that he is now A-Rank. Midorikawa runs up to Jin, cheering his name, begging for a match. Yoneya informs Yūma and Osamu that Jin saved Midorikawa from a Neighbor, which was why he had joined Border. Midorikawa then calls Osamu "senpai," and apologizes for trying to purposefully humiliate him in front of others. Osamu is relieved to admit that he lost 24 times to Kazama and that the rumor about his tie was blown out of proportion. Yūma and Midorikawa reconcile, and form a friendly rivalry. Midorikawa pleads for Jin to let him join Tamakoma if he defeats Yūma. Osamu, Yūma, and Yōtarō astride Raijinmaru leave with Jin, and Yoneya pouts that he wasn't able to duel with Yūma. The spectators whisper about Yūma's outstanding victory, but also about the mysterious Osamu, whom Yūma calls "captain" and seems to be close with Jin and Kido.
Jin asks Yūma and Osamu about their impressions fighting Midorikawa. Yūma calls him strong, while Osamu admits he couldn't read him at all. Yūma then explains he usually fights people as if they are animals. His father once told him that since humans are illogical, it is sometimes better to examine people's behavior than their logic. Disheartened by the realization of the difference in strength and ability between himself and Yūma, and understanding how hard he will have to train in order to catch up to other people who are already pushing themselves to the limit, Osamu stands in the elevator muttering to himself after the others have exited. Yōtarō eventually calls him back to reality.
They enter a room with a large virtual display and are greeted roughly by the head staff of Border. Shinoda explains that they anticipate a large attack in the near future. After the bombing incident where numerous people were injured, they are looking for ways to reduce injuries and ask for Yūma's opinion as a Neighbor. Kinuta explains further that they haven't been able to gather enough information and as a Border agent, they expect Yūma to give them his opinion or which country might attack and what kind of attacks might be used. Yūma says it would be better to ask his partner, and Replica emerges from his sleeve, surprising everyone. Replica introduces himself as a special Trion Warrior created by Kuga Yugo and affirms that he has information from traveling around the Neighborhood. Before Replica will give them the information, however, he demands that Yūma's safety be guaranteed by Kido. Osamu realizes that Yūma is testing Kido with his Side Effect. Kido quickly agrees, saying that as long as Yūma follows Border regulations, he will be protected. Yūma doesn't react, leading Osamu to believe Kido is telling the truth, and Replica proceeds to tell them about the world of Neighbors.