Jung Soo Jung or better Krystal Jung is an ordinary girl who newly transferred school from San Francisco to Seoul. She doesn't have any friends excluding her older sister Jessica who is a member of the popular girl group SNSD better known as Girls' Generation .  Althought she's really popular in school because of her famous sister, they sometimes get frozen of her ice cold look. Personally she doesn't know what K-pop is but she only knows SNSD.