At the prestigious Seitei Gakuen, a renowned educational institution in Tokyo, Minami Yuuri embarks on her second year as a teacher. Transitioning from instructing middle schoolers to teaching high school grammar, she eagerly anticipates her new role—only to find herself assigned to class 3-E, known as 'Class X.' This senior class, infamous for its lack of academic prowess, has a reputation for driving teachers to retirement due to stress-related illnesses. Undeterred, Minami takes on the challenge of connecting with these students, including the rebellious 'B6' leaders, and guiding them towards a path of higher education.