Hina returns to her hometown, only to find her former high school divided into two rival factions, each identified by the color of their uniforms: black for the followers of the aggressive and violent Nishizaki, and white for those who align with the misanthropic and fastidious Isshiki. Additionally, a group of independent students, known as the "grays," opt to wear their own clothing, refusing to be swayed by either faction. As Hina becomes entangled in the conflict between the two leaders, tensions escalate, threatening to turn violent.