Choi Yeon-woo can't see the color. I was stuck only on the disappearance of my mother, who disappeared three years ago. He meets Yuhan, who suddenly causes a color rush, a phenomenon in which colors suddenly appear in the whole school through the tampering of his aunt. While trying to distance himself from being obsessed with his own, his curiosity never stops. In the meantime, people related to clues about her mother's disappearance begin to appear.