Aya Toujou is a central figure in the story, initially introduced as a shy and academically gifted middle school student whose plain appearance, characterized by large glasses and an unassuming hairstyle, conceals her true beauty. Her birthday is January 14th. The first character of her family name, Tou, means "east," a detail that aligns with a thematic naming convention among the main female characters.

Personality-wise, Aya is reserved, timid, and kind to a fault, often placing the needs of others before her own. Despite her quiet and clumsy nature, she possesses a rich inner world and a remarkable talent for creative writing, which serves as her primary motivation. Her dream is to become a successful novelist, a goal she pursues with dedication throughout her school years and beyond. A pivotal moment in her life occurs when Junpei Manaka, the protagonist who aspires to be a film director, discovers a fantasy novel she has been writing in a notebook. His genuine admiration for her writing and his shared passion for creative storytelling spark a deep emotional connection between them. This bond is so significant that she decides to forgo admission to a prestigious all-girls high school, Oumi Academy, in order to attend Izumizaka High School with Manaka, the only school with a film club.

In the story, Aya plays a crucial role as the primary scriptwriter for the Film Studies Club, crafting the narratives for the films that Manaka directs. Her literary talent earns her several prestigious awards and recognition, and she eventually has her first novel published while still in high school. Her development is closely tied to her transformation and her unspoken feelings. When she replaces her glasses with contact lenses and lets her hair down, her natural beauty is revealed, making her a school idol and confirming to Manaka that she is the mysterious "girl with the strawberry panties" he has been searching for since their first encounter on the school rooftop. For much of the series, her deep affection for Manaka remains a secret due to her shyness, even though he is initially attracted to her. Her key relationships are defined by this romantic tension with Manaka, her rivalry and friendship with Tsukasa Nishino, and her camaraderie with the other members of the film club, including the more forward Satsuki Kitaouji.

Aya's emotional journey culminates in a heartfelt confession of her long-hidden love after learning that Manaka has rekindled his relationship with Nishino. The confession is regretfully rejected, leading to a period of heartbreak over an unrequited first love. This experience becomes a significant part of her personal growth, teaching her about the depths of her own feelings. Ultimately, she is able to find closure and move on, channeling her experiences into her career. After graduation, Aya achieves her dream of becoming a highly successful novelist, winning numerous awards, including the prestigious Naoki Prize, and establishing herself as a respected author. Even in her success, she continues to cherish the dream of one day having Manaka adapt the very first novel she wrote in her notebook into an award-winning film, symbolizing the lasting, albeit transformed, impact he had on her life and art.