Lihua Ritsuka, who lives in a nostalgic street Shikocho, is a girl who is a second-year student at Shiko Gakuen High School. While looking forward to the occasional contact with his older brother Lindo who is studying in the UK, he spends a peaceful day with his mother. One day, she is summoned by the student council president, Rem Katsuki, whom the students of the academy yearn for, and has a strange encounter with them at the "Third Library" where the student council members gather. Demons, vampires, exorcists. Around the "forbidden magic book", various thoughts began to revolve around her—is it a human or a demon? This is the story of a girl who was charmed and loved by the devil.