A fiercely competitive police officer and an idealistic prosecutor, former high school classmates, reunite while investigating a nationwide serial murder case, pulling them into both a dangerous pursuit and an unresolved personal past.
Despite Yeong Beom's blame to Tae Joo, Tae Joo gives all of his heart and strength for Seok Man's retrial and Hye Jin's case steadily. He even stars on Ji Won's news and reveals the culprit of Hye Jin's case openly. Through the news, the situation goes chaotic. Shocked, Yeong Beom and Sun Yeong go to Si Yeong's office, and they blame him. But Yeong Beom requests Si Yeong to say the truth in the court as a last chance. Will Si Yeong say the truth? And will Seok Man's honor be restored?
As suspicion toward Gi Beom grows, Tae Joo is confused because the circumstances point to Gi Beom as the killer, but he hesitates to arrest him for some reason. After another murder case happens, he tries to find the missing Gi Beom to ask about everything, being sure that Gi Beom is the killer. Si Yeong, who was attacked by the killer, wakes up, and he reconciles with Tae Joo. But with the emergence of Si Yeong's brother, the situation of the investigation unit becomes complicated.
