The exploits of FBI Special Agents Fox Mulder and Dana Scully who investigate X-Files: marginalized, unsolved cases involving paranormal phenomena. Mulder believes in the existence of aliens and the paranormal while Scully, a skeptic, is assigned to make scientific analyses of Mulder's discoveries that debunk Mulder's work and thus return him to mainstream cases.
The Lone Gunmen reveal the (possibly fake) secret history of the Cigarette Smoking Man to Mulder and Scully; from a young captain in the U.S. Army recruited to assassinate President Kennedy, to becoming the mysterious man in the shadows at the height of a global conspiracy.