The X-Files: I Want to Believe is a 2008 American supernatural thriller film directed by Chris Carter and written by both Carter and Frank Spotnitz. It is the second feature film installment of The X-Files franchise created by Carter, following the 1998 film. Three main actors from the television series, David Duchovny, Gillian Anderson, and Mitch Pileggi, reappear in the film to reprise their respective roles as Fox Mulder, Dana Scully, and Walter Skinner.

Dr. Dana Katherine Scully, MD, is a fictional character and one of the two protagonists in the Fox science-fiction, supernatural television series The X-Files, played by Gillian Anderson. Scully is a Federal Bureau of Investigation (FBI) Special Agent and a medical doctor (MD), partnered with fellow Special Agent Fox Mulder for seasons one to seven and seasons 10 and 11, and with John Doggett in the eighth and ninth seasons. In the television series, they work out of a cramped basement office at FBI headquarters in Washington, DC to investigate unsolved cases labeled "X-Files." In 2002, Scully left government employment, and in 2008, she began working as a surgeon in Our Lady of Sorrows, a private Catholic hospital – where she stayed for seven years, until rejoining the FBI. In contrast to Mulder's credulous "believer" character, Scully is the skeptic for the first seven seasons, choosing to base her beliefs on what science can prove. She later on becomes a "believer" after Mulder's abduction at the end of season seven.