An immature mother, Eun-mi, and her daughter, Jin-hee, live their daily lives like sisters. Jin-hee works at the Wolsan Police Station, and due to an incident, she is unjustly demoted to calm public opinion. Jin-hee goes home looking forward to drinking cold beer with her mother, but she sees something she had never imagined.

While examining Mrs. Na, a patient who came to the orthopedic clinic, Eun-mi sees bruises at her back and tells Jin-hee that she suspects domestic violence. They also suspect that Mrs. Na's grandson was also abused. Eun-mi, who hates people who hit their family, gets angry again.