Kozue Ayuhara is a determined and enthusiastic high school volleyball player who serves as the central figure of the story. Originally from Tokyo, she transfers to Fujimi Academy in a suburban area to recover from a frail constitution and chronic illness, hoping the cleaner air will improve her health. It is there that she rediscovers her passion for volleyball, a sport she had been forced to abandon. Intelligent and naturally athletic, she possesses remarkable physical strength and agility that quickly make her stand out on the court.

Her personality is a blend of warmth and fierce tenacity. Kozue is kind-hearted, compassionate, and often full of positivity, using her love for volleyball to inspire those around her. At the same time, she is strong-willed, direct, and occasionally quick to argue or even resort to a fistfight when provoked. This mix of approachability and grit defines her interactions and earns her a reputation as both a loyal friend and a formidable competitor.

Kozue’s primary motivation is to become the best volleyball player in Japan. Her dream is to represent the country on the national team, and she pursues this goal step by step, advancing from the school district league all the way to the international championship. This ambition drives her to endure rigorous training and to continually push beyond her limits, even as she encounters the darker aspects of success, such as crushing expectations, self-doubt, and the envy of others.

Within the story, Kozue moves from a newcomer who initially falls in with a group of delinquent girls to the captain and ace attacker of the Fujimi Academy volleyball team. After a dispute with the existing school team, she forms her own squad and leads them to a narrow victory, which allows her and some of the delinquents to join the official team. Her talent and leadership quickly become evident, and she is appointed captain. Over the course of the series, her journey takes her through intense tournaments, personal losses, and confrontations with powerful rivals, all while learning about friendship, teamwork, and the true meaning of competition.

Several key relationships shape her path. Her closest friend and teammate is Midori Hayakawa, who begins as an egotistical rival demanding the spotlight but eventually becomes a trusted second-in-command after a series of conflicts and reconciliations. Her cousin Tsutomu Ichinose, the vice president of the student council, provides steady encouragement and emotional support. The team’s coach, Shunsuke Hongō, employs strict, spartan training methods that challenge Kozue physically and mentally; beneath his stern exterior, he cares deeply for his players. Among her rivals, Shellenina of the Soviet Union stands out, a skilled opponent who defeats Kozue in their first high-stakes meeting and pushes her to grow stronger for a rematch.

Kozue’s development traces a clear arc from a sickly girl who could not play sports to the nation’s top attacker. Along the way, she endures heavy personal losses and grapples with the pressures of leadership and fame. These experiences forge a more mature, resilient athlete who understands that success is not just about individual glory but about lifting up her team. Her notable abilities include exceptional game intelligence, the capacity to read situations and react almost instantly, powerful spikes, and a relentless work ethic. She constantly refines her techniques and never gives up, even in the face of overwhelming odds. Through her unwavering spirit and remarkable skill, Kozue Ayuhara becomes an enduring symbol of perseverance and devotion to a sport she loves.