Towa Takanashi is a descendant of Sirens who has fallen for her classmate, Kei Shibuya. She faces a terrible dilemma: her feelings of love are inseparable from the Siren’s primal instinct to eat the object of her affection. Summoning all her courage, she confesses her feelings to Kei, only to be rejected on the spot. Before she can process the devastation, she discovers that Kei is hiding a dark secret of his own, a revelation that binds their fates together in an unexpected way.

The story takes place in a contemporary Japanese high school setting where supernatural creatures exist alongside humans. Towa is sweet-natured but constantly battling the predatory hunger that defines her Siren heritage. Kei initially seems like a typical aloof male lead, but his secret places him in a unique position regarding Towa’s dual nature. The narrative explores how these two individuals navigate trust and danger when one literally craves the other.

Over the course of its run, the manga shifts its tone significantly. What begins as a supernatural romantic comedy about a girl trying not to devour her crush gradually transforms into a darker thriller with horror elements. The central conflict escalates as Towa struggles to suppress her instincts while external forces and Kei’s secret put them both in peril. The story concludes after a relatively brief serialization, bringing Towa’s internal war between affection and appetite to a final, decisive resolution.