About the title
Lee Na-mi, who works as a marketer at a young company, falls asleep on public transport one day on her way home and loses her mobile phone. The gadget is found and returned to the girl by a mysterious guy, Oh Joon-young, but before that he installs spyware on it that allows him to track her movements, interests, tastes, and personal life. Meanwhile, police detective Woo Ji-man, investigating the murder of a young woman, confirms his worst fears when he finds evidence at the crime scene pointing to his son, Oh Joon-young.