In a world where terrifying creatures called Utsuro feed on a unique form of bio-energy known as “Nectar,” which only exists in young girls— Natsumi, a member of the anti-Utsuro organization Hyakkaen, lives each day gripped by the fear of being devoured. But one day, a mysterious girl with overwhelming strength appears before her… and everything begins to change. A dark and intense battle-action series where girl vs. monster is more than just survival—it's a fight for existence.