This drama tells the story of a surrogate mother who enters the home of the woman holding the secret to her child’s death. Kim Yoon Jin (Song Yoon Ah) is a former psychiatrist. To do what is best for her husband and son, she quit her job. Kim Yoon Jin had a daughter, but her daughter died and she carries a sense of guilt over her daughter’s death. She wants the best for her son who is about to enter a university. Kim Yoon Jin decides to hire an expert to help her son enter a good university. The expert is mysterious.