At Murasaka Higashi High School, where 80% of the students are vampires, the vampires hold a position of extreme power. Consequently, most humans enter a 'Chinotomo' relationship, consensually providing blood to vampires. In reality, the vampires use blood-supply addiction to make humans subservient. Among them, Guest has not made a 'Chinotomo' yet, because they are waiting to find their 'destined one' among the human boys to enter that bond with.