Ritsuka Tachibana, known for her academic excellence, faces a startling summons from the student council accused of rule-breaking. Interrogated by Rem Kaginuki and his council mates, it soon becomes apparent that hidden agendas are at play. However, this incident marks only the start of Ritsuka's troubles. After her mother's abduction, Ritsuka is thrust into a conflict between vampires and devils vying for the powerful 'Grimoire,' a coveted object with world-altering capabilities, in which Ritsuka has a mysterious involvement. The unexpected return of her protective brother Lindo offers a glimmer of hope for normalcy, yet even he harbors secrets. As Ritsuka navigates alliances, doubts arise about her allies, and she grapples with conflicting emotions towards the charming members of the student council.