Mao Mizusawa is the main female character in the anime. She is introduced as a childhood friend of Kouichi Sanada and Kazuki Aihara. At the start of the story, she returns to Japan after living in France for several years and moves in with Kouichi and his mother. She is seventeen years old and a third-year high school student. Before her stay abroad, she was described as a studious and somewhat awkward person, but she returns having transformed into a confident and more mature young woman. She is very active, energetic, and cheerful by nature, though she is notably not a morning person and can be sluggish early in the day. Her primary motivation is to reconnect with her old friends and adjust to her new life back in Japan, but she also harbors a strong desire to help those around her, particularly Kouichi. She takes on the role of supporting Kouichi in his attempts to start a relationship with his classmate Yuumi Hoshino, even as her own feelings for him become a source of internal conflict. Her role in the story is central, as her return sets much of the romantic tension and emotional development in motion. In terms of key relationships, her bond with Kouichi is the most significant; she has known him since childhood and her feelings for him grow deeper as the series progresses, which eventually compels her to move out of his house to avoid complicating his pursuit of Yuumi. Her friendship with Kazuki Aihara is also important, as he is another childhood friend who recognizes her immediately upon her return. She also attracts the attention of a fellow student named Eiji Kai, who develops romantic feelings for her, though she does not reciprocate them. Over the course of the series, Mao undergoes notable development as she navigates her own emotions, grapples with jealousy and self-awareness, and learns to be honest with herself about what she wants. She matures from a supportive and somewhat self-sacrificing friend into someone who can acknowledge her own desires and confront the emotional challenges of love and friendship. While she does not possess any supernatural or extraordinary abilities, she is shown to be capable of cooking and handling household tasks, and she has a talent for music and singing, often using that as a personal outlet. Standing at about 162 centimeters with a February 27 birthday, Mao is an outgoing and spirited presence whose journey is defined by the tension between her desire to support others and her own emerging romantic needs.