The X-Files is an American science fiction drama television series created by Chris Carter. Episodes of the series were the first broadcast on the Fox Television network, starting with the "Pilot" episode on September 10, 1993.

The series revolves around Federal Bureau of Investigation (FBI) special agents Fox Mulder (David Duchovny), and Dana Scully (Gillian Anderson) who investigate X-Files: marginalized, unsolved cases involving paranormal phenomena. Mulder believes in the existence of aliens and the paranormal while Scully, a medical doctor and a sceptic, is assigned to scientifically analyze Mulder's discoveries, offer alternate rational theories to his work, and thus return him to mainstream cases.

There are two types of episodes:

Mythology episodes deal with the show's overall story arc, usually involving the Syndicate, Colonization, Hybrids, or Super-Soldiers. Most of the episodes that fall into this category were, in 2005, released in official Mythology DVD sets.

Monster of the Week episodes deal with some type of supernatural or paranormal creature or sometimes a simple criminal with a unique gift. They are usually separate from mythology episodes.

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