"Signal" is not just a detective story. The tvN drama, which stars Kim Hye Soo, Lee Je Hoon and Jo Jin Woong, combines crime investigation with the paranormal. Although the thriller is inspired by a real-life series of crimes known as the Hwaseong Serial Murders," in the drama solving the case relies on a detective who sends signals from the past.

The detective sends his messages through a mysterious radio frequency on an old two-way radio, providing clues lost to time.

The real Hwaseong Serial Murders, in which 10 women were raped and murdered, happened in the 1980s. They took place from 1986 to 1991 and then suddenly stopped.

The crimes captured the imagination of the nation because of their brutality and the fact that the killer was never found. The murders have been the subject of several dramas and films, including Bong Joon Ho's film "Memories of Murder." The tvN drama "Gap Dong" also focused on the case. In each retelling the story, directors, writers and producers attempt to untangle the mystery and provide the answers that the real-life detectives never found.

"Signal" will likely do the same, when it begins on January 22.

Lee Je Hoon, last seen in the drama "Secret Door," plays a criminal profiler with an independent streak. Kim Hye Soo, who appeared in the drama "Queen of the Office" and the film "Coin Locker Girl," is his hard-hitting detective boss. Jo Jin Woong, who appeared in the drama "The Full Sun" and the film "Assassination," is the former detective who is working on the case in the past.

Kim Won Suk, who directed the hit drama "Misaeng" as well as the dramas "Monstar" and "Sungkyunkwan Scandal," will direct the drama. Kim Eun Hee, who wrote the screenplays for "Three Days," "Ghost" and "Sign" will write the "Signal" screenplay.

The drama will air on Friday and Saturday nights.