Who is the Real Killer

Dong Sik wants to stop Bo Kyung from looking into the murder case happened at Goseong Chemical, so he follows her and offers help. Dong Sik gets to know Nergui by chance when he sneaks into Goseong Chemical. Nergui asks for Dong Sik’s help and tells him that Jin Goo doesn’t kill himself. Meanwhile, an open investigation begins after a dead body is found in Goseong Chemical, and In Woo finds out that Dong Sik and Bo Kyung actually know each other.