Dr. Go, a hospital director, is consumed by rage when his wife has an affair with Dr. Jung and his young daughter, Young-ah, disappears and is found dead. He believes his daughter's death is due to his wife's infidelity. In revenge against his wife, Dr. Go adopts the daughter of Young-ah's killer. Unaware of this, his wife lovingly raises the child, naming her Yang-ja. Years later, upon learning that Yang-ja is her enemy's daughter, Mrs. Lee begins to mistreat her, shocked and betrayed. Yang-ja, upon discovering the truth of her birth as an adult, attempts suicide out of guilt. However, after being dramatically rescued, a doctor who arranged the adoption reveals a twist: Yang-ja was not the killer's daughter. The family is left facing irreversible ruin and belated regret.