Younes stumbles upon other murders where the common thread is the blood relation of the victims to one another, and he realizes they are dealing with a serial killer.
A new murder is reported, and the handling of the case is transferred from Younes to Mohsen Mowla, but Amir-Ali Nadaf prevents Younes from leaving the investigation.
Nadaf recounts to Younes the story of the setup he was framed with years ago. Simultaneously, Sohrab, the only child of the person who saw the face of the serial killer, returns to Iran because his father is still alive.
Younes, now almost certain that Amirali Nadaf is not the killer, enlists his help to solve the mystery, while Siavash also offers to assist, unaware that Amjad is the one responsible for his father's death.