KIM Ji-young is an ordinary Korean woman in her 30s who is often distressed by her everyday life as a full-time mom and housewife. Although being married to the man she loves and the struggle of raising a baby girl have forced her to give up on many things, Ji-young believes she is content in life.

However, her husband, Dae-hyeon, notices that life is hitting Ji-young harder than she realizes. Worried, Dae-hyeon turns to a psychiatrist saying, “My wife is turning into someone else,” as Ji-young begins to speak strikingly similar to her mother, her best friend who died while giving birth, and her late grandmother.