A teenage girl named Haru Okamoto is entering high school with a passion for katanas. She discovered the sword in her grandparents' home when she was young and they promised to give it to her as an adult. However, at 15 years old, Haru does not see herself as an adult yet. Fortunately, she finds solace in the almost-defunct high school Iaido club where she can explore her love for Japanese swords while also learning about teamwork and overcoming her fear of boys. Through this experience, Haru will come to realize that her fascination with katanas has a deeper meaning than she ever imagined.