Signal (Korean: 시그널) is a South Korean television series written by Kim Eun-hee, directed by Kim Won-seok, and starring Lee Je-hoon, Kim Hye-soo, and Cho Jin-woong. It was inspired by real-life criminal incidents in Korea, including the Hwaseong serial murders. The first season aired on tvN from January 22 to March 12, 2016, every Friday and Saturday at 20:30 (KST). In March 2024, a second season was confirmed to be in production.
The series received widespread acclaim from audiences and critics alike for its story and performances. It is also one of the highest-rated Korean dramas in cable television history with a peak audience viewership of 12.544% - only next to Reply 1988 (18.803%) at the time of its release in 2016.
Contents
Plot
In present-day 2015, criminal profiler Park Hae-young (Lee Je-hoon) finds a mysterious discarded walkie talkie; inexplicably, the person at the other end, Detective Jae-han (Cho Jin-woong), is from the past, and addresses him familiarly, even though Hae-young has never met him. Hae-young is able to solve a 15-year-old kidnapping and murder case involving a former classmate from his childhood with Jae-han's help. The success of this case triggers the formation of a cold case team, led by Detective Cha Soo-hyun (Kim Hye-soo), who has been searching for Jae-han, her long-lost mentor and unrequited love, for the past 15 years.
With Jae-han's help from the 1990s, Hae-young solves other cold cases that have remained unsolved for years and is drawn into the mystery surrounding Jae-han's disappearance in the year 2000. As they try to fix the past and catch the criminals, unintended consequences follow in the present.
Cast
Main
Lee Je-hoon as Park Hae-young
The jaded and hotheaded criminal profiler who finds the walkie-talkie by chance, and uses his connection with Jae-han to solve cold cases.
Kim Hye-soo as Cha Soo-hyun
The first female police officer in the Special Task Force, she becomes the leader of the Seoul cold case squad. She has been searching for Jae-han, her mentor and unrequited love, for 15 years, believing him to be dead.
Cho Jin-woong as Lee Jae-han
The socially inept but virtuous and quick-tempered detective from the past who establishes a rapport with Park through the walkie-talkie. His timeline during his communication with Park spans from 1989 to 2000.
Supporting
Police officers
Jang Hyun-sung as Kim Bum-joo
The corrupt police superintendent.
Jung Hae-kyun as Ahn Chi-soo
The section chief and supervisor of the Seoul cold case squad who acts as Bum-joo's lackey but appears morally gray.
Kim Won-hae as Kim Gye-chul
A police officer who joins the Seoul cold case squad and often serves as comic relief.
Jung Han-bi as Oh Yoon-seo
A colonel.
Lee Yoo-joon as Jung Han-ki
A forensic scientist and member of the Seoul cold case squad, often seen with Detective Kim.
Kim Min-kyu as Hwang Eui-kyung
A junior officer that cleans up the Seoul cold case squad's work area and admires them.
Extended
Kim Hyun-bin as young Park Hae-young
Kang Chan-hee as Park Sun-woo
Hae-young's older brother who was convicted in the high school gang rape case and died by suicide after being released.
Yang Dae-hyuk as Hong Won-seo
A detective.
Lee Moon-soo as Lee Jae-han's father
Reception
Upon its premiere, the series attracted attention for weaving actual cases into its plot and attained high ratings. With its finale rating of 12.54%, it is one of the highest rated Korean dramas in cable television history. It received praise for its solid acting, tightly constructed plot and detailed and sophisticated direction; and enjoyed success internationally in China and Japan.
The drama went on to win several awards from different award-giving bodies, including Best Drama, Best Screenplay for Kim Eun-hee, and Best Actress for Kim Hye-soo at the 52nd Baeksang Arts Awards, as well as another Best Actress award for Kim and the Daesang (Grand Prize for Television) for Cho Jin-woong at the tvN10 Awards. Cho also won the Daesang at the 1st Asia Artist Awards for his performance.
Adaptations
A Japanese remake of the series starring Kentaro Sakaguchi was aired from April 10 to June 12, 2018, on Fuji TV.
On October 23, 2019, Unknown Number, a Chinese remake of the series, started airing on Tencent Video.
On April 2, 2021, a Japanese film of same name was released based on the Japanese television series adaptation of the Korean original - it continued from where the television series had left off.
On January 20, 2023, a Thai remake of the series titled 23:23, was aired on True4U.
On April 24, 2024, an Indian remake of the series titled Gyaarah Gyaarah, has premiered on August 9, 2024, on Zee5.
