Kuroiwa Medaka was born in a temple and is currently a monk in training. Because of his temple's rules, he can't interact with girls - and what's more, he doesn't even know how to regularly socialize with them. Mona, the "queen bee" of the school, however insistently tries to make him fall in love with her, but he always ignores her in order to maintain the rules of his temple.

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!