With Main collapses, everyone she knows comes together in a bid to save her life. But soon, she is faced with a life-or-death decision, one that she must discuss with her family.

Combat-use Trion Soldiers attack when a gate opens in Osamu’s school just outside of the Forbidden Zone. Worried he’s not strong enough, Yuma tries to stop Osamu from fighting back, but Osamu’s determination to save the other students is limitless.

Viza and Hyuse continue to pursue Chika, but Yuma and Jin arrive just in time. Yuma faces off against Viza while Jin battles Hyuse. Osamu and Karasuma lead Chika and the C-rank agents to Border HQ. However, Enedora's rampage has the HQ in chaos!

Yuma's revealed why he came from the other world. Chika's resolved to join the Border Agency so she can go to the other world in search of her friend and her older brother.

Osamu reaches out to Yuma and Replica. He and Chika learn some critical information about Neighbors from Yuma, but they're soon discovered by two A-Rank agents, Shuji and Yosuke; they're searching for a Neighbor in human form...

Osamu doesn't know how to deal with his new reputation as "the guy who tied with Soya Kazama". He is soon challenged by one of his fellow agents to a Rank War.

Yuichi finally reveals his "Wind Blade" technique with the Black Trigger. As his battle with A-Rank vets Kei and Soya reaches its climax, the Arashiyama Unit shows up in support and clashes with the Miwa Unit. Who will emerge victorious?!

Tamakoma-2 starts individual training in preparation for the B-Rank rank wars. Osamu visits Arashiyama for shooter training. Chika meets a young boy during group sniper training. Yuma meets Kageura, an agent that No. 4 attacker Murakami has never beaten.

Border seeks a way to counter the new Trion soldier, Rabbit. Yuma prevents Trion soldiers from infiltrating the city, but is mistaken for the enemy and attacked by the B-rank Chano Unit. Meanwhile, an Ilgar Trion Soldier menaces Border headquarters!

Ninomiya Squad, Kageura Squad, Azuma Squad and Mikumo Squad face off! As tensions mount, each team targets Osamu and closes in. Meanwhile, the two strongest B-Rank agents, Ninomiya and Kageura, assess the situation. Can Mikumo Squad survive the onslaught?