Destroy thy Neighbor! A gate to another dimension has burst open, and invincible monsters called Neighbors invade Earth. Osamu Mikumo may not be the best among the elite warriors who co-opt other-dimensional technology to fight back, but along with his Neighbor friend Yuma, he'll do whatever it takes to defend life on Earth as we know it.

With only seven seconds left until the crossroads, time is running out. Black Triggers face off as Miwa activates Fujin to bring the invasion to an end. But did they really escape the worst possible future?