Episode 4

S1 E4: The Kidnapper sent a picture of Hyun Woo together with Ji Eun, who was reported as missing. Detective Cha worked on Ji Eun's case before he took the Hyun Woo case. The second mission video was delivered via email. Ji Eun served as a narrator in the video, saying they have to prove the murder committed by a doctor, Dong Min. If they fail to prove that Dong Min is guilty of a murder within a day, Hyun Woo will die.