Kozue Ayuhara is a cheerful but unexceptional second-year student at Fujimi High School who loves volleyball and plays on the school team. She is not the captain nor the most skilled player, often looking up to her best friend, the talented and wealthy Midori Hayakawa. Kozue’s life is turned upside down when she receives a shocking summons to join the All-Japan Youth National Team, a spot that everyone, including Midori, believed was destined for the far more accomplished Midori. The selection is made by Daigo Inokuma, a notoriously brutal and dictatorial national coach with a fearsome reputation for dragging failing players out of the gym by their hair. The unexpected news breeds immediate hostility; Kozue’s teammates, led by the resentful captain Miyuki Onuma, become cold and accusatory, while Midori herself grows distant and consumed by jealousy, fracturing their once-close friendship.

Despite her crippling lack of confidence, Kozue reports to the grueling national training camp. There, she finds herself surrounded by Japan’s most talented and combative players, including Michiru Sanjo, a hostile and rebellious girl with a dark past, and the Yagisawa sisters, known for their complex triple attack. In a move that baffles everyone, Coach Inokuma names the overwhelmed Kozue as the acting captain of the national team, a role for which she feels completely unfit. He imposes physically punishing training regimens and psychological tests, seemingly trying to break her spirit to forge her into a weapon. The situation escalates when Inokuma schedules the national team’s first practice match against Kozue’s former team at Fujimi High, forcing her to compete against the friends who now view her as a traitor. Her school coach, Shunsuke Hongo, harbors a deep-seated hatred for Inokuma, blaming the ruthless national coach for the death of a friend who collapsed from overexertion years earlier.

The drama follows Kozue as she navigates these treacherous waters, suffering a serious leg injury that requires surgery and facing dismissal from the national team after a scheme orchestrated by Inokuma to test her resolve. When she is cut, she returns to Fujimi High to discover the volleyball federation plans to disband the school team unless they win the national championships. Kozue rallies her former rivals and teammates, including a now-repentant Midori, to fight for their survival, unaware that her expulsion was secretly part of Inokuma’s ruthless plan to create an unbeatable team by forcing her to mature through adversity. The narrative also explores Kozue’s personal life, particularly her relationship with Tsutomu Ichinose, a kind young man who works at a ramen shop, whose tragic death in an accident becomes a pivotal emotional trial she must overcome to continue playing. The series culminates with the reconstituted national team competing in an international tournament, where Kozue must finally reconcile her personal sacrifices with her genuine love for the sport to achieve victory on the world stage.