Cha Woo-Kyung works as a child counselor at a children’s center. Her life is perfect. She enjoys her job, she is married to a gentle, competent husband and she is pregnant with her second child. An accident changes Cha Woo-Kyung's life. She faces various incidents and digs up the truth. Meanwhile, Kang Ji-Hun works as a detective. He firmly believes criminals should be punished by the full extent of the law. He holds pain within himself from his past that he hides.