Cha Woo Kyung (Kim Sun Ah), works as a children's counselor in a children's center. She has it all, her life is perfect. She enjoys her job, she is married to a gentle and caring husband and is pregnant with her second child. It all changes when suddenly an accident changes her life. From that point forward she will have to face several incidents and end up discovering the truth.
Meanwhile, Kang Ji Hun (Lee Yi Kyung), works as a detective. He firmly believes that criminals should be punished by law. He suffers a lot because of a traumatic past that he doesn't want to talk about.