Two twin sisters, who are orphans, get separated when one of them gets adopted. However, fate brings them together during their darkest hours as their lives get switched.

A School girl called Go Eun-Byul goes off on a schooltrip to Teongyeong. While in Teongyeong she meets her twin sister Lee Eun-Bi for the first time. Lee Eun-Bi is having a hard time in life and is considering suicide. Lee Eun-Bi replaces Go Eun-Byul's live after her dissapear and have to live like her and lie to everyone.

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.