The Border Defense Agency plans an escape expedition into the neighbor's dimension after successfully repelling the Aftokrator attack. However, only A-rank teams can be sure of securing a slot, just like in prior scouting excursions. Osamu Mikumo and the other members of Tamakoma-2 swiftly battle their way to the top as the B-rank warfare go on in an effort to get promoted before the operation starts. A new Neighbor ship is now sailing toward Border Headquarters. Forces are hurriedly dispatched to repel the assailants once it is discovered that they are aiming for the Border Expedition Ship. However, the organization is in chaos since there are fewer squads available as a result of the ongoing rank warfare. The destiny of the vital exploration ship is questionable in light of the Neighbors' most recent onslaught.