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, a photograph taken just before the death of a two-year-old boy yields evidence of some supernatural intervention which piques Mulder and Scully's curiosity.
When another death in the family occurs, the grandmother of the remaining child requests the aid of some Romanian ritualists, named the Calusari, in order to cleanse the home of evil.
In Murray, Virginia, Maggie (Helene Clarkson) and Steve Holvey (Ric Reid) visit an amusement park with their children.
The agents later visit the Holveys, and Scully grows suspicious of Maggie's elderly Romanian mother, Golda (Lilyan Chauvin), who is seen drawing a swastika on the boy's hand.
Concerned for Charlie's safety, Scully suggests involving the social worker named Karen Kosseff (Christine Willes).
However, tragedy strikes when Steve is accidentally killed in his garage, and when the police investigate his death, they discover evidence of ritualistic sacrifices in Golda's room.
[4] Christine Willes, who plays the part of Agent Kosseff, reprises her role; she originally appeared in the earlier episode "Irresistible".
Fox's standards and practices department, on the other hand, took issues with the initial cut of Steve's strangulation scene; in the end, the sequence was kept but the actor's face was obscured to "soften the impact".
[5] "The Calusari" is the only episode of the series to have received an explicit rating of "18" in the United Kingdom by the BBFC for "occasional strong horror" and themes involving "demonic possession".
[8] Robert Shearman, in his book Wanting to Believe: A Critical Guide to The X-Files, Millennium & The Lone Gunmen, gave the episode a largely negative review and rated it one-and-a-half stars out of five.
The writer called it a "pale retread of The Exorcist" and noted that many of the episode's elements, like the chicken-sacrificing grandmother and the Calusari members, were "tremendously crass".
[9] Shearman, however, did enjoy the episode's dialogue, praising one scene in particular where the spirit of Michael torments his mother by asking to be taken to the amusement park and ride the train that killed his younger brother.