731 (The X-Files)

731 (The X-Files)

"731" is the tenth episode of the third season of the American science fiction television series The X-Files. It premiered on the Fox network on December 1, 1995. It was directed by Rob Bowman, and written by Frank Spotnitz. "731" featured guest appearances by Stephen McHattie, Steven Williams and Don S. Williams. The episode helps explore the series' overarching mythology. "731" earned a Nielsen household rating of 12, being watched by 17.68 million people in its initial broadcast.

The show centers on FBI special agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) who work on cases linked to the paranormal, called X-Files. In this episode, Mulder risks his life infiltrating a train carrying a human-alien hybrid. Meanwhile, Scully tries to uncover the truth about her abduction. "731" is a two-part episode, continuing the plot from the previous episode, "Nisei".

The production of "731" involved several stunts, including the explosion of a retired railway car. The episode's production was successful for two members of the crew—earning director of photography John Bartley an American Society of Cinematographers award nomination for his work, and securing Bowman the job of directing the series' subsequent film adaptation, The X-Files.