Mamoru Yoshimura was accepted into a school for Beatrices due to his high intellect. "Beatrices" are people who have special abilities. On his first day, he meets Ayako Takasu, AKA the Beatrices' Angel of Death, a pretty and popular female student who has exceptional Beatrice abilities. During their first encounter, Ayako, who is usually a cold person and is regarded as somewhat of a loner, suddenly confesses her feelings for Mamoru. After Mamoru becomes inducted into the Student Council as Ayako's aide, he becomes involved in the dangers and mysteries of the Beatrices.