Sekang High School is the most prestigious private high school in Seoul's Gangnam District, and Go Eun Byeol is the most popular girl there. Meanwhile, her identical twin Lee Eun Bi is living in an orphanage and is being bullied at school. Then one day, Eun Byeol mysteriously disappears. Soon after, Eun Bi loses her memories and is mistaken as being Eun Byeol. Eun Bi then starts living her life as Eun Byeol.