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.
As the year 2000 draws closer, the agents are up against a man from the Millennium Group who believes that he can bring about the end of the world on the 31st of December if he resurrects four former members from the dead. To gain more insight into the group and its practices, Mulder and Scully enlist criminal profiler Frank Black to assist them in the investigation.