Kim Yoon-jin (Song Yoon-ah) is a successful ex-psychiatrist who quits her job to become a full-time housewife after the mysterious death of her daughter. She carries a sense of guilt with regards to her daughter’s death. She suspects her daughter’s death is not what it is proclaimed to be and tries to find out the truth. Not only is she a successful ex-doctor, she is also the head on the board of directors to her father’s medical foundation.

Because of her son’s education, she goes all out to hire Lisa Kim (Kim So-yeon). Lisa is a top expert who helps students to get to the most prestigious universities and helps them achieve the path of an elite.

However, Lisa is a mysterious lady. She is a “surrogate mother”. At the same time, she is also trying to find and connect back with someone who was like a sister to her when she lives in the orphanage where she grew up then. She is also known as Kim Eun-young in the drama.

Kim Yoon-jin’s husband, Han Jae-yeol (Kim Tae-woo), is an elite police chief. He graduated from the police academy with top honors.

Yoon-jin get to know Ha Jung-wan (Song Jae-rim), who is a homicide detective. He is rash and blunt. However, he is the only person that believes in Kim Yoon-jin’s doubts about her daughter’s death. He helps her to find out the truth behind it.

Who is Lisa Kim exactly? Does she know the secret and truth of the death of Yoon-jin’s daughter? What happen to her in the end?

Is Jun-wan able to find out the truth and help Yoon-jin to identify how her daughter die?