To uncover the dark secrets of Nobel Academy on behalf of a grieving father, an agency plants a plasma-form agent codenamed Akiko as a new teacher. Upon her arrival, Akiko discovers a disturbing atmosphere where female students are plagued by uncontrollable sexual urges and systemic harassment that the administration ignores. As Akiko attempts to investigate the influence of the Headmistress and the Aizawa sisters, she quickly finds herself targeted by the school's sadistic power structure.
Akiko Yagami continues her undercover investigation at Nobel Academy, discovering that the students' hypersexuality is caused by a drug in the water supply orchestrated by the Aizawa Concern. The conspiracy seeks to harvest the "energy of youth" to grant eternal life to the mysterious Lord Hyouma. After the Aizawa sisters and Headmistress Tachibana target her students, Akiko utilizes her full agent capabilities to stop the ritual. With Lord Hyouma's demise and the plot exposed, Akiko completes her mission and leaves the academy.