The tvN TV drama "Signal" registered a national rating average of 10.9 percent for the 11th episode on Friday, proving to be a big hit after "Reply 1988" syndrome.

Starting with a 6 percent rating for its first episode on Jan. 22, "Signal," which screens every Friday and Saturday, has been gaining an additional 1 percent with each following episode on average, according to Nielsen and reports on Saturday.

The drama, starring Kim Hye-soo, Cho Jin-woong and Lee Je-hoon, is about detectives working on unsolved cases as the statute of limitations for first-degree murders is scrapped.

The story travels back to 1999, when Lee Jae-han (played by Cho Jin-woong) is in a fictional city investigating a case involving the sexual assault of a middle-school-aged girl by more than 10 schoolboys. The boys are sons of wealthy and powerful families who team up with the police to have another schoolboy set up.

The narrative then fast-forwards to 2015, when Lee, who had been aware of the truth about the rape case, is found dead by fellow investigators Cha Soo-hyun (Kim Hye-soo) and Park Hae-young (Lee Je-hoon). (Yonhap)