Akane Mizuno is a third-year middle school student and the female protagonist of her story. She is a dedicated member of the school's track and field club, where she is recognized as the ace, particularly excelling in short-distance running and winning prizes at various competitions. Alongside her athletic commitments, she is a diligent student who consistently earns good grades, balancing her sports and academic life with serious effort.

In terms of personality, Akane presents a calm exterior but is often self-conscious, shy, and prone to nervousness, especially in social situations or when interacting with someone she likes. To manage her anxiety, she carries a small, potato-shaped mascot named Benippo, which she gently squeezes to build up her courage. Despite her timidity, she possesses a greater maturity regarding social interactions than some of her peers and is considered fundamentally competent. Her motivations are rooted in navigating the complexities of her first romance while dealing with the ordinary pressures of school life and looming changes in her family situation.

Akane's role in the story is centered on her gradual, awkward, and heartfelt relationship with her classmate, Kotarou Azumi. Their connection begins with furtive glances and a mutual, unspoken attraction, eventually developing into a secret relationship that they navigate with tenderness and anxiety. Her key relationships include her family, particularly her older sister, and her friends, such as Chinatsu Nishio. She also faces a complicating dynamic with Takumi Hira, the track club president who harbors feelings for her. A significant challenge arises when her father's job necessitates another family move, this time to Chiba, forcing her to confront the prospect of a long-distance relationship with Kotarou.

Throughout the narrative, Akane undergoes notable development. She must cope with the stress of her parents' marital issues and her own anxieties about an uncertain future. The prospect of moving away fills her with worry that her relationship with Kotarou will not survive the distance. Her emotional journey culminates in a moment of profound realization when she reads a novel Kotarou wrote and published online, understanding the depth of his commitment to her, which moves her deeply. Beyond her athletic talent as a skilled runner, her most notable ability is her emotional resilience and her method of self-soothing, represented by her reliance on the Benippo charm.