One day, the colossal tower, "Babel" suddenly appeared in the city of Tokyo. High school student Taiga holds a belief of, "Not standing out is the best." While he dreams of chasing after his sister from the self-defense forces who went missing inside Babel, his daily life still continues to be boring, and the same as usual.
However, on one certain day, the "time to fight" finally confronts Taiga! Young man, fight and survive in the tower! Grasp it! A new era filled with a battle of "superpowers" and an "unprecedented" tale of survival, begins now!