Hiromi Oka enrolls at a high school renowned for its tennis club and begins playing the sport inspired by the famed Madam Butterfly. She expects to enjoy tennis alongside her best friend, Maki, but things shift when the new coach, Mr. Munakata, chooses Hiromi to join the team for an upcoming tournament and subjects her to rigorous training. Determined to succeed, Hiromi pushes herself through each challenging lesson, and her dedication pays off as she earns the role of the team’s representative in the junior match tournament.