This drama is based on the 2011 novel Fantastic Girl (판타스틱 걸) by Kim Hye Jung (김혜정) which was published on 2011-Jan-20 via Bilyongso.
Ban Ha Ni (Choi Kang Hee) is 37-years-old and a single woman. She holds a temporary position at work, which makes her nervous that she might get fired. She is generally servile and timid. Considering her current state, she does not want to be single. One day, 17-year-old Ban Ha Ni from the past comes to 37-year-old Ban Ha Ni. 17-year-old Ban Ha Ni is totally different from her older self. The younger Ban Ha Ni is bright and optimistic.