"The Alternative Factor" was the 20th episode of Star Trek: The Original Series, in the show's first season, first aired on 30 March 1967. The episode was written by Don IngallsMA, directed by Gerd OswaldMA and novelized in Star Trek 10 by James Blish.We are joined by the Transporter Room's Chris! Investigating a "winking out" of the universe, the Enterprise finds a time traveler named Lazarus who has counterparts in both the positive and antimatter universes. If both versions of Lazarus meet at the same time—outside of a magnetic corridor between universes—it will mean the end of everything!