Miyuki Yoneyama, a mathematics teacher, was becoming involved in an inappropriate relationship with Kouichi, the student council president in her homeroom class. However, she learns that Kouichi has started a relationship with Ayatsuji Himeko, an educational trainee. Overwhelmed by forbidden feelings towards her students and her pride as a homeroom teacher, Miyuki finds herself increasingly losing her sanity, becoming chaotic, and falling deeper into turmoil amidst the rivalry among the female students over a single male student.