The beautiful girl Zheng Da En (played by Son Ye-jin) has been dependent on her father Shun Man (played by Kim Kap-soo) since she was a child. No matter how the surroundings change, her father is still the person closest to her. During Da En's job search, a kidnapping case that shocked the country 15 years ago was brought up again. At that time, a child named Han Caijin was kidnapped and killed, and the kidnapper's whereabouts remained unknown. Seeing that the statute of limitations was about to expire, a film adapted from the incident was released nationwide, and at the end of the film, the suspect's telephone recording of that year was made public. Da En, who watched the movie with her friends, was horrified to find that the voice called "the devil's whisper" was so similar to her father's voice. She tried to investigate her father's past, but she never gained anything. One day, a man named Shen appeared in the lives of the father and daughter. He seemed to know about Shun Man's unspeakable past, and brought darkness to this seemingly ordinary family...