With the final matches of the B-Rank Wars coming up, Tamakoma-2 gets its chance to go up against Suzunari-1, Azuma Squad and Kageura Squad again. This time is different—Hyuse is an official member of Tamakoma-2 and ready to shake up the competition. But Suzunari-1 has a trick up their sleeve when Taichi suddenly cuts the lights in the arena, causing a total blackout.

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.