On the TV show "The X-Files," what is the name of Fox Mulder's sister, whose disappearance set in motion his search for the truth?

"The X-Files" (1992 - 2002) is a series that revolves around its two main characters. They have been defined early in the conception of the show as the "believer" and the "skeptic". The "believer", Fox Mulder (David Duchovny), was created as a character with a defining personal motivation. It concerns the disappearance of his younger sister, Samantha. She was taken away during his childhood, which he believes was the result of an alien abduction. The creation of the "skeptic" is presented in the character of Dana Scully (Gillian Anderson). She is called a "real" person, who maintains a doubting attitude about values, plans, statements, and the character of others. She is ... a person who doubts the truth of things until some actual proof is provided.

The belief about the abduction of Mulder's sister Samantha was explored in the episodes "Pilot", "Conduit", and "Miracle Man". This abduction would go on to become one of the central themes for the whole series. With alien abductions, they have been the subject of numerous conspiracy theories in books, films, and television shows. "The X-Files" is notably one of the best known story lines to speculate about a specific alien abductee, Samantha Mulder.