Lee Eun Bi and Lee Eun Byeol are identical twins, separated after Eun Byeol is adopted. Eun Bi goes to Tongyeong Girls High School, while Eun Byeol goes to Sekang High School, one of the most pretigious private high school in Seoul, but the two both are bullied at school. When Eun Byeol mysteriously dissappears, Eun Bi takes on Eun Byeol's life and goes to her school to reveal exactly what happened to her twin sister.