Jung-han, the leading police officer at the special investigations in charge of violent crime, has to raise his sister's young daughter after she and her husband are killed in a car crash.

Jung-han gets into an awkward predicament while joining a baby yoga lesson with an older women from the same village. Jung-han finds out that Ye-seul, his first crush, lives in the same apartment, raising her son Hoon-gu on her own after a divorce.

Ma Jung-soon, Jung-han's grandmother, visits Jung-han and wants to see Eun-ae. However, Eun-ae and Jung-soon disappear together. Meanwhile, Ye-seul bumps into Jung-han after she struggles with parenting.

After Ji-young and Ye-seul have a fight over child issues, Jung-han tries to comfort Ye-seul. However, this attempt leads to misunderstanding. Meanwhile, Ji-young, an expert in parenting, devises a scheme to kick Ye-seul's son out of kindergarten.

Jung-han is overcome when Eun-ae suddenly starts suffering from enteritis. He calls Mrs Ma to account over Eun-ae's sickness, claiming that it is her fault. Meanwhile, Ji-young prepares for her daughter's birthday party.

Mothers in the apartment start worrying about a child molester near the building. A notice prohibiting urination on the street is put up on the building's wall. Later, Jung-han is suspected of being a pervert by mothers in the apartment.