Song Jin-Woo (Kim Dae-Gun) has worked as a non-permanent contract employee for the past 4 years at Moojin Girls' High School. He is a good teacher and dreams of a school where no one is left out. New contract teacher, Yoo Sung-Pil (Moon Yoo-Kang), comes to Moojin Girls' High School. When Song Jin-Woo was a high school student, he was bullied by Yoo Sung-Pil and other students.