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.
Scully fears that Mulder has gone to the other side when she sees him assisting a federal suspect escape custody. In truth he has infiltrated a terrorist group testing a deadly biological weapon that can eat through a person's flesh.