Earth is under constant threat from Neighbors, invincible monsters from another dimension that destroy our way of life. At least we have the elite warriors of Border, who co-opt alien technology to fight back! Meet agent Osamu Mikumo, not the best, but along with his Neighbor friend Yuma, he'll do whatever it takes to defend life on Earth as we know it.

The Rank Wars is racing towards a conclusion as the final squads battle to determine their final rankings. Katori is as difficult to deal with as ever, and her squadmate Wakamura is having none of it. But mid fight, Katori suddenly tells Wakamura that he gets to call all of the shots. Will Wakamura be able to handle the pressure? And with the Rank Wars over, the Away Team selection exams are on the horizon. But first, Jin and Rindo need to have a little chat with a handful of familiar Neighbor invaders from Galopoula...about Yotaro.