First season: There was a strange murder of the girl in 1995 in Louisiana. In 2012 case of murder is opened repeatedly as there was a similar murder. Police decided to interrogate the former detectives who were investigating the murder of a girl in 1995 in order to advance in the investigation. Detectives learned while working on the murder investigation that dragged on for 17 long years.
Second season: The action takes place in the fictional town Vinci, California. Murder of the official of city administration endangers the large business project connected with construction of the new railroad. The interagency group comprising the local detective Ray Velcoro, Ventura County Sheriff's Office CID Ani Bezzerides and traffic police officer Paul Woodrugh were entrusted to investigate this deal. Own investigation is started also by the head of a local organized criminal group Frank Semion who lost some million dollars because of the incident. At each of them is not only the purposes, but also the skeletons in the cupboard.