Chihiro Tachibana, known for her stern demeanor despite her beauty, secretly harbors romantic feelings for a kendo club member. Alongside her best friend Rino Sakuragi, she manages the club until her ordinary life takes an unexpected turn with the arrival of the charming and flirtatious Shou Hinase, a kendo practitioner from a different school. Despite a bumpy start, their paths converge in high school when they find themselves in the same class. United by destiny, their passionate and tumultuous love story, woven by a red thread, unfolds.