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 sealed environment test continues! But now the focus shifts to the brain-straining battle simulation exercises. Each team tries to create the ultimate fighting force, using a limited amount of points for each unit and their abilities. But it's not just about strength--fooling your opponent is just as important. Get ready for some intense strategy sessions and devilish trickery!