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.
Mulder, back on the X-Files but alone for the first time, investigates a series of vampire-like murders in Los Angeles and finds himself falling for the one woman that may be the prime suspect.