The show centers on FBI special agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) who work on cases linked to the paranormal, called X-Files. In this episode, Scully grows suspicious of Mulder when she thinks he may be helping a terrorist organization. Scully begins to wonder if he is now a traitor to the FBI. It is eventually revealed that Mulder is working as a mole in the group, and he is trying to stop them before they are able to use a biological weapon—that may have been created by members of the U.S. government—which causes rapid degeneration of human flesh.