This is a monster of the week episode and you could also consider it a Christmas special. Mulder calls Scully out on Christmas Eve to investigate a haunted house which as you can imagine she is not terribly happy about in the first place. Once inside, they are trapped and the fun begins. The house is haunted by the spirits of a couple that committed murder/suicide. Their goal is to lure couples and potential victims to do the same. Throughout this episode the ghosts try to convince Mulder and Scully that the other is trying to kill them.
This episode is relatively simplistic by X-Files standards with only four actors and basically one set. For that reason, I don’t consider this to be the most re-watchable of episodes but I think it works especially well for the Christmas themed episode that it is. The ghosts use illusion to trick the agents and it is almost dream sequence like so in that regard it reminds me a little of “Triangle” only a few episodes before this one. I like this episode better though, in large part probably because there is lots of Mulder AND Scully in this one both interacting together and apart.
Overall I would give this one 3.5/4 stars.