"I am not a hero, and I never wanted to be one of those narcissists."

After the night of Hyakki-Yagyo took everything that was left of him, Yuuki Shinohara was forced to become a "hero." Saving people from the Fearborn in order to save the only person left in his life, Sakura.

But the deeper he delves into the mirror world, the more he realizes that the "heroes" he despises are not merely narcissists. They take lives, sacrifice the weak, and call it justice. And when someone he once saved begins to retaliate in the same way, Yuuki is faced with a question he cannot avoid:

What is the difference between a Hero and a Monster?