"Mayo elle Otokonoko" centers on the life of Sawa, a high school student who navigates the complexities of identity, relationships, and societal expectations. Sawa, assigned male at birth, has always felt more aligned with a feminine identity and begins presenting as a girl at school. This decision sparks a range of reactions from peers, teachers, and family, highlighting the challenges of self-expression in a rigidly gendered society.

The narrative explores Sawa's journey as she forms friendships, confronts prejudice, and seeks acceptance. Key relationships include her childhood friend Makoto, who struggles to reconcile his feelings for Sawa with societal norms, and Aoi, a classmate who becomes a steadfast ally. The story also delves into Sawa's family dynamics, particularly her strained relationship with her father, who initially struggles to understand her identity, and her supportive mother, who becomes a source of strength.

As the series progresses, Sawa's experiences at school and in her personal life intertwine, revealing the broader societal pressures faced by transgender individuals. The plot addresses themes of self-discovery, resilience, and the importance of community, while also portraying the emotional toll of discrimination and misunderstanding. Through its nuanced portrayal of Sawa's life, "Mayo elle Otokonoko" offers a thoughtful exploration of gender identity and the pursuit of authenticity in a world that often resists change.