At three years old, Joong A is adopted by a family living in Ireland, where she later becomes a doctor. Unfortunately, Joong A loses her adoptive parents due to her adoptive brother. She experiences overwhelming guilt after losing her family and makes her way back to Korea to end her own life. However, as soon as she arrives, she becomes involved with Kang Guk and marries him. Guk feels a sense of pity toward Joong A and tries his best to help her regain her will to live. While trying to make sense of her life, Joong A gains employment at a hospital. There, she comes across Jae Bok, whose life she saves by administering CPR. She continues to run into Jae Bok and eventually falls in love with him. However, while Jae Bok continues to exchange feelings with Joong A, he can't bring himself to end things with Si Yeon. How will this story of four ill-fated people end?