Kazuna’s family has a long‑standing history of a disease that induces an uncontrollable, vampire‑like craving for blood. Unaware of this legacy, he was sent to live with the Eda couple during his childhood. As the illness begins to manifest within him, he meets his older sister Chizuna, who has suffered from the same condition since early childhood. Knowing the heavy burden the disease places on its sufferers, Chizuna strives to ease her brother’s plight and help him learn to control his urges, but…