Hibiki Amawa, a young and passionate physical education teacher, struggles to find a job due to his unconventional teaching methods and lack of experience. Desperate for employment, he applies to a prestigious all-girls school, Seito Sannomiya Academy, only to discover that the institution has a strict policy of hiring only female staff. Determined to secure the position, Hibiki disguises himself as a woman, adopting the persona of "Hibiki Hanamaru." His transformation involves altering his appearance, voice, and mannerisms to convincingly pass as female.

As Hibiki begins his new role, he faces numerous challenges in maintaining his disguise while navigating the complexities of teaching and interacting with students. His classes are filled with a diverse group of girls, each with their own personalities and struggles. Among them is Aoi Saito, a reserved and academically driven student who initially clashes with Hibiki due to his unorthodox teaching style. Over time, Aoi begins to open up, influenced by Hibiki's genuine care and dedication to his students.

The series explores themes of identity, gender roles, and the importance of empathy in education. Hibiki's dual life creates moments of tension and humor as he balances his responsibilities as a teacher with the constant risk of exposure. His interactions with the students gradually reveal their individual stories, highlighting issues such as self-doubt, family expectations, and societal pressures. Through his unconventional approach, Hibiki encourages the girls to challenge their limitations and embrace their true selves.

Supporting characters include the strict and traditional school principal, Mitsuko Sannomiya, who enforces the school's policies with unwavering authority, and Chihaya Harukaze, a fellow teacher who becomes suspicious of Hibiki's true identity. The dynamic between Hibiki and Chihaya adds an additional layer of intrigue, as her curiosity threatens to unravel his carefully constructed facade.

The narrative progresses with a mix of comedic and heartfelt moments, culminating in a resolution that addresses the consequences of Hibiki's deception and its impact on the school community. The series ultimately underscores the value of authenticity and the transformative power of education, as Hibiki's journey leaves a lasting impression on both his students and colleagues.