Mulder and Scully explore the thin line between sanity and madness when they track a serial killer who claims to be possessed by an evil spirit.
After a series of paranormal deaths occur at a Mexican migrant camp, Mulder and Scully go on the trail of a mythical blood-sucking creature known as "El Chupacabra."
The FBI decides to offer Danny and Lexi information to assist them in their search for Cleopatra; Farouk deals with a loose end.