The Hangwon-dong serial killer hides in Soo Hyun’s memories and Hae Young talks Jae Han into being nice, for once.
A note from the past leads Jae Han and Hae Young to a serial killer, and a terrifying encounter for Soo Hyun.
A ghost from the past comes to haunt Han Se Kyu, and Jae Han’s killer is revealed.
Han Se Kyu’s case leads down a rabbit hole of fake deaths, corruption, and murder.
Disaster falls on the cold case squad, as Hae Young and Jae Han race against the clock to make it right.
Hae Young learns more about Jae Han, and a new case starts, with disastrous results.
Our team catches the Gyeonggi Nambu serial killer, but there are dire consequences for being late.
The detectives make progress on the case, but the progress leads to the possible return of the Gyeonggi Nambu killer.
The detectives of the past and the present are set on the trail of the most famous cold case in Korea, the Gyeonggi Nambu murders.
“Signal” starts off with an action-packed first episode.