Signal
Season 1
16 episodes
Communicating via a walkie-talkie that transcends time, a profiler from 2015 and a detective from 1989 join forces to tackle crimes and injustice.
Episode 1
You're Doomed
Profiler Park Hae-young hears a man calling his name through a discarded two-way radio. The voice starts talking about an unsolved crime.
Episode 2
We Still Have a Chance
The statute of limitations is lifted after the suspect's arrest. Hae-young joins Soo-hyun's team for the newly established cold case squad.
Episode 3
We Can Prevent the Killings
Reality changes after Hae-young exchanges information with Jae-han. Hae-young tries to work together with Jae-han in 1989 to prevent the next murder.
Episode 4
We Found the Killer
The ninth victim is Won-kyung, the woman Jae-han loves. A driver turns himself in, but Soo-hyun and Jae-han determine that his son is the real killer.
Episode 5
Changing the Past Alters the Present
Hae-young starts to investigate Jae-han's disappearance. Jae-han's former colleagues get suspicious about seeing Hae-young digging into the past.
Episode 6
Catch Him by All Means
Seeking vengeance for the events that lead to the death of his daughter, Kyung-tae commits a kidnapping after getting out of prison for burglary.
Episode 7
We Must Dig Deeper
Jae-han arrests Se-kyu for the serial burglary case, but the culprit is freed after serving a short sentence; Kyung-tae still commits murder.
Episode 8
How Are You Alive?
Soo-hyun and Hae-young notice a connection between the burglary case and Da-hye, the woman who killed herself twenty years ago.
Episode 9
Hongwon-dong Case
Hae-young learns that Chi-soo and Jae-han met in 1999 during a case in Inju. After serving time for the crime, Hae-young's brother had killed himself.
Episode 10
Someone Has to Stop the Bad Guys
The bodies discovered in the mountains appear to be more victims of the 1997 serial murder case. Jae-han learns that Soo-hyun became team leader.
Episode 11
The One Last Case
Hae-young and Soo-hyun arrest Jin-woo after coming to the conclusion that he is the killer. Hae-young asks Jae-han about the Inju rape case.
Episode 12
The Case Was Manipulated
Hae-young becomes a suspect for the murder of Chi-soo. Jae-han realizes who the principle offender of the attack on Hye-seung is.
Episode 13
The Real Assailant
Soo-hyun and the others mourn after confirming that the remains belong to Jae-han. Hae-young learns that Jae-han used to look after him in the past.
Episode 14
Not Now, but Maybe in the Past
Hae-young realizes the possibility that his brother could have been murdered after learning from Hye-seung that Sun-woo was not guilty.
Episode 15
Is It Really You?
Hae-young is arrested for the murder of Chi-soo. Soo-hyun hears Jae-han apologizing over the radio for not being able to prevent Sun-woo's death.
Episode 16
If You Don't Give Up
Hae-young is in critical condition after being shot while meeting with Sung-bum. In 2000, Jae-han has been captured by Bum-joo.
