Akihito Kanbara is a high school sophomore in the literature club who believes himself to be a “Meganest”, and although he appears to be human, he is actually half Y?mu, which makes him invulnerable to wounds, due to the fact that he can heal so quickly, and also immortal. One day, Akihito meets freshman Mirai Kuriyama when it appears as if she is about to attempt suicide by jumping off of the school rooftop. Mirai is isolated because of her ability to manipulate blood, which is considered heresy even among other members of the underworld, so she is shunned. Soon after Akihito saves Mirai, disturbing events begin to arise.