‌Beretta

Younes stumbles upon a murder case in which an entire family has been killed during a birthday celebration.

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.

Younes obtains clues that relate to the contaminated vaccines case in which Amir-Ali Nadaf had committed murders.

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.

Amir-Ali Nadaf reveals a big secret to Younes: a case from the past that plagued Nadaf and changed the course of his life.

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.