The exploits of FBI Special Agents Fox Mulder and Dana Scully who investigate X-Files: marginalized, unsolved cases involving paranormal phenomena. Mulder believes in the existence of aliens and the paranormal while Scully, a skeptic, is assigned to make scientific analyses of Mulder's discoveries that debunk Mulder's work and thus return him to mainstream cases.
After a strange yellow rain kills a migrant girl, her family believes that a mythical creature el chupacabra was the cause and that it has manifested itself inside her fiancé's brother, who has since disappeared.