Number of Episodes: 16

Released Year: 2016

Main Plot:

Signal is a Korean crime-thriller drama inspired by real-life unsolved cases. The story follows detectives from different timelines who communicate through a mysterious walkie-talkie. By connecting the past and present, they attempt to prevent crimes and catch culprits who had escaped justice for years. With suspense, emotions, and moral dilemmas, Signal delivers a powerful narrative about justice and fate.

Main cast:

• Lee Je-hoon as Park Hae-young (Profiler, present timeline)
• Kim Hye-soo as Cha Soo-hyun (Detective, present timeline)
• Cho Jin-woong as Lee Jae-han (Detective, past timeline)

Episodes Summary

Episode 1: The Mysterious Walkie-Talkie

One day in 2000, Park Hae-young, a little child, waited outside the Seoul elementary school for his classmate Kim Yoon-jung after class.Yoon-Jung was never seen outside after class. Later, Yoon-jung and an unidentified woman leave the elementary school, and Hae-young bolted to the police station because he feared he was going to die after witnessing the woman shove Yoon-jung out of the school. The officers dismissed him because they had arrested a suspect.

The actual kidnapper eludes detection, but Yoon-jung’s body is discovered a few days later. This terrible event causes Hae-young to lose faith in law enforcement and think that the police are not trustworthy when it comes to safeguarding the weak.

Hae-young was elevated to lieutenant and profiler in the police force in 2015, fifteen years after the incident. His encounter with Yoon-jung’s former schoolmate while investigating a case of celebrity abuse brings back painful memories of her unsolved murder. On the same night, a walkie-talkie that had been stored in the police junkyard and left there springs to life. At the other end there is a man’s voice, essential, strong and foreigner. With a live hearing air, the man presents himself as Lee Jae-Han and begins to interrogate him about her kidnapping.

Startled but intrigued, Hae-young initiates a second investigation into the crime right away. He considers the odd woman he had seen with Yoon-jung in 2000 while following this course. His discovery of the old CCTV footage suggests that the woman was present with the victim, confirming that the wrong man was arrested. Due to the persistence of Hae-Young, the case is reopened and the falsely accused defendant, who had been imprisoned for years, eventually is excluded.

Cha Soo-hyun, a devoted detective who served under Jae-Han and spent years attempting to resolve his esoter disappearance, is interested in a fresh case. She initially finds the direct and disobedient conduct of Hae-young disappointing, but she eventually comes to appreciate his deep profiling abilities and penance.

The walkie-talkie is restarted at the same time. The exact fact is that JaeHan’s voice was telling at that time, only one could be known by those who were part of the first investigation. Ultimately, Hae-Young learns that the voice is actually of a detective Jae-han from the year 2000 instead of the present. Despite his dissatisfaction with the unavailable link, he is determined to pay attention.

The reason for Yoon-jung’s death is ultimately revealed at the end of Episode 1: she was abducted by the lady Hae-young had seen years before, but the original investigation disregarded her. Hae-young is very troubled by the unfairness of the wrongfully convicted guy receiving a fifteen-year sentence. But at the same time, he starts to worry that the strange link to Jae-Han could reveal the outcome of other cases.  As the show ends, the walkie-talkie returns to life and the voice of Jae-Han breaks peace, serving as a chilling reminder, the past and present are unwavering.

Episode 2: Clues Across Time

It is almost time to wrap up the 2015 kidnapping case of Yoon Jung. Yoon Soo Ah, the suspect, is being pressured by the police to confess because the statute of limitations is about to expire. There is an obvious sense of stress since they know that this is their only chance. Soo Ah is approached by Detective Cha Soo-hyun, the lead investigator, who subtly suggests that the DNA found on a second victim’s glasses could establish her guilt. Soo Ah remains calm despite being under a lot of stress and refuses to recognize anything.

In an attempt to secure a breakthrough, Park Hae-young takes a chance by creating DNA evidence to persuade her that the police can prove her involvement. The scheme fails despite his meticulous preparation. As the clock strikes the end, Soo Ah remains steadfast, officially ending the statute of limitations. Disappointed and helpless, the team looks on in frustration as the culprit escapes.

Hae-young is sent to a newly created cold case investigation section, which is headed by Detective Soo-hyun, following this failure. They started with horrific Hwaseong serial killings, which took place decades ago and are still unresolved. To find out what the first investigation ignored, the team gathers to go through old reports, images and assistant documentation.

Hae-young is going through the cold case files that night when the abandoned walkie-talkie comes to life. The voice of Detective Lee Jae-Han has been immediate and familiar since 2000. A missing woman who may be the next victim of the Hwaseong Killer is focused on frustration.

As Jae-han describes the pitch-black fields and roads, Hae-young listens in shock, calling her name and frantically attempting to get to her in time. The radio waves appear to bring the past and present together, creating an instant tension.

Jae-han does his hardest, but he can’t save the woman. Another victim was added to the list of serial killers in 2000 when her body was found the next morning. Hae-young is seated in 2015, speechless and in shock at what he has witnessed.

A melancholy note ends the show. The regretful and melancholy tone of Jae-han’s voice wanes over the walkie-talkie.  The sound of Jae- han’s voice and sadness is on the tone walkie-talkie. Their pain on their failure to protect the woman through time. As Hae-Young hears in 2015 in a calm form, he is shaken by the weight of these unresolved cases and odd, inexplicable connections that bind it to their past. Although the investigation of cold cases has begun, the reality of failure and loss still allows work, creating a stressful and emotional environment.

Check this another thriller Korean drama with full of suspense.