Park Moo Jin and Kang In Ha are a married couple. Park Moo Jin works as a high school teacher and Kang In Ha runs a bakery. They enjoy their lives with their children. Their peaceful days soon turn into a hellish experience. Their son, who is in the 3rd grade of middle school, is seriously injured due to school violence. Park Moo- in and Kang In Ha try to reveal the truth.
Meanwhile, Oh Jin Pyo and Seo Eun Joo are a married couple. They are both from wealthy families. Oh Jin Pyo is the chairman of a private school foundation inherited from his family. They have never experienced failure or lacked anything. They have a son who makes trouble. The parents coverup for their son's misbehavior.