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. "Unusual Suspects", however, functions as a flashback episode: in 1989, two salesmen and a federal employee join forces when they meet Susanne Modeski, a woman who claims that she is being pursued by her supposedly violent ex-boyfriend, an FBI agent named Fox Mulder. A sequel to the episode was later filmed during the series' sixth season, entitled "Three of a Kind".