Park Moo Jin (Park Hee Soon) and Kang In Ha (Choo Ja Hyun) are a married couple. Park Moo Jin works as a high school teacher and Kang In Ha runs a bakery. Their peaceful days are soon destroyed when their son is seriously injured due to school violence. Park Moo Jin and Kang In Ha try to reveal the truth behind school bullying. On the other end of the spectrum is Oh Jin Pyo (Oh Man Seok) and Seo Eun Joo (Jo Yeo Jeong), who are a wealthy and powerful couple. Oh Jin Pyo is the chairman of a private school foundation, which he inherited from his family. They have never experienced failure. They lack nothing besides from a troublemaker son, who is a bully. Regardless, they will stop at nothing to cover up their son's crimes.