Disenchantment

S09E16 William

Doggett discovers an intruder in the X-files office attempting to steal documents related to Mulder's sister. The intruder, a man with severe scars, accuses government conspirators of causing his disfigurement and claims that Mulder was his source of information and assisted him in breaking in. Although he won’t reveal Mulder's location, his extensive knowledge of the X-files raises Doggett's suspicions that he may actually be Mulder. Meanwhile, Scully's anxiety for her son intensifies after he is injected with an unknown substance, forcing her to make the difficult decision to send him away for his protection as the mystery surrounding William deepens.