When a deadly yellow rain falls in a migrant workers camp and kills a young woman, Agents Mulder and Scully come to investigate what happened. After questioning the family the agents learn that they believe a mythical creature is responsible for the death and before long Mulder and Scully are on the trail of a mythical beast known as El Chupacabra. Mulder and Scully have to work out where the beast will go next before it can kill anyone else.