Go Ha-neul (Seo Hyun-jin) decides to become a teacher due to her gratitude towards one of her teachers who saved her life. When she grew up years later, she was offered an opportunity for a short term teaching position at a private school. There, through struggles, she grows as a teacher.
Park Seong-soon (Ra Mi-ran) is an experienced teacher, who is also the head of the career counselling department of the school. She is a known workaholic. She is a mentor to Go Ha-neul.
Do Yeon-woo (Ha Joon) is a Korean Language teacher who is very passionate about teaching and is very popular with the students. He believes that talent will win over any office politics, and does not get involved in it.