Haru Okamoto, a teenage girl who adores katanas, is just now entering high school. When she was little, she happened upon a katana in her grandparents' house. In their haste to get the blade from her, they agreed that when she was an adult, the katana would be hers. However, to her dismay, they do not agree that a 15-year-old, immature, excitable Haru is an adult! Luckily, she finds another outlet for her love of Japanese swords, the almost-defunct high school Iaido club! As Haru searches for new club members and tries to get over her fear of boys, she will become aware that her affinity for Japanese swords has a deeper source than she could have imagined!