Signal

Park Haiying, a psychological profiler of the long-standing case squad, is a heretical figure in the police world who is dissatisfied of the police. In order to make a living, Haiying wastes his talents in investigating the celebrities’ privacy and then sells it to the media, until a 10-year-old wireless machine rings. The policeman Li Caihan, who is an upright man, being active in the police in the 1980s. Caihan contacted Haiying with a wireless machine and they begin to resolve the past unsolved incidents.