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 doing her first patrol for the Namchon Police Station, Jin-hee hears a report of a burglary at their house, and Eun-mi manages to catch the culprit. However, upon hearing the reason for the theft and that the culprit will not be detained since it's his first offense, Eun-mi, the "neighborhood crazy bitch," takes matters into her own hands.

Eun-mi sees the wounds of Na Gyeong-ran, who came to the orthopedic clinic as a patient, and tells Jin-hee that domestic violence is suspected. Jin-hee even discovers the grandson of Na Gyeong-ran, who is suspected of having been assaulted by her parents, but it is difficult to separate them because they are her family. Enraged at the people beating her family, Eun-mi gets angry again.

Eun-mi, Mi-jung, and Jin-hee have a wonderful time together, sharing stories of the challenging moments when Eun-mi endured domestic violence. Eun-mi confides in Jin-hee, disclosing that it was Mi-jung who encouraged her to undergo an abortion. A few days later, Eun-mi and Jin-hee learn about the discovery of a deceased girl's body in the news.

After spotting an unknown man lurking near her house and observing her suite from a distance, Jin-hee decides to chase after him. She doesn’t realize then who this guy is, but she thinks he could be a possible suspect in the recent murder case. Meanwhile, Eun-mi unexpectedly encounters someone from her past, a former love interest, and his sudden reappearance after all these years deeply troubles her.