One Son (2) - S6.E12

The Cigarette-Smoking Man reveals all the government secrets from the past 50 years in order for his son, Jeffery Spender, to join him in his work. Mulder learns that the final stage of the conspiracy will soon begin with the hybridization of the Syndicate members, and he must stop it from happening. Agent Spender deceives his father and arranges for Mulder and Scully to be reassigned to the X-Files, which doesn't sit too well with the Cigarette-Smoking Man.