"Hitohira" is a slice-of-life manga series that centers on Mugi Asai, a shy and introverted high school student struggling with self-confidence. After transferring to a new school, Mugi is encouraged by her classmate Nono Ichinose to join the school's drama club. Despite her initial reluctance and fear of public speaking, Mugi gradually becomes involved in the club's activities, finding herself drawn to the world of theater. The drama club is led by the passionate and somewhat eccentric Kairi Sanada, who pushes Mugi to confront her insecurities and grow as a person.

The narrative explores Mugi's journey of self-discovery as she navigates the challenges of performing on stage, forming friendships, and overcoming her anxiety. Nono, a cheerful and supportive friend, plays a significant role in helping Mugi adapt to her new environment. The story also delves into the dynamics within the drama club, highlighting the personal struggles and aspirations of its members, including the talented but reserved Chitose Nakama and the competitive Rena Aoki.

As Mugi becomes more involved in the club, she begins to develop a sense of belonging and confidence, though not without setbacks. The series portrays her gradual transformation from a timid and uncertain individual to someone who learns to embrace her strengths and face her fears. The drama club's preparations for various performances serve as a backdrop for character development, emphasizing themes of perseverance, teamwork, and personal growth.

The relationships between the characters are central to the story, with a focus on friendship, mentorship, and the occasional romantic tension. Kairi's guidance and Nono's unwavering support are pivotal in Mugi's journey, while the interactions among the club members reveal their individual personalities and struggles. The series balances lighthearted moments with emotional depth, creating a relatable and engaging narrative about overcoming personal obstacles and finding one's place in a new environment.