The story, according to Fox Mulder, was that - during World War I - Maurice and Lyda were "star-crossed lovers" who made a "lover's pact" and took their own lives. From that point on, they could be found haunting the house every Christmas Eve. Three double murders took place in the house over the following decades, leading Mulder to believe that the ghosts were involved.
Involvement with Fox Mulder and Dana Scully
In 1998, he and Dana Scully visited the house, where they encountered the ghosts. Maurice, in particular, attempted to psychoanalyze Mulder, describing his quest as a "para-masturbatory illusion" to compensate for his own social shortcomings and unfulfilled desires. Scully learned that Maurice was indeed a ghost when she noticed the gaping entry and exit wounds on his head that were otherwise concealed by a hat. Maurice and Lyda seemed to take great pleasure in terrifying Mulder and Scully.
After taking the illusion of Mulder, Scully experiences a bullet wound to her chest after having been shot by Maurice, in the form of Mulder, with Mulder's firearm. In another room, Lyda takes of the illusionary form of Scully and shoots Mulder with her firearm in a similar fashion to how Maurice shot Scully.
As the two agents are crawling to the front door, they eventually realize that Maurice and Lyda were playing tricks on them and their bullet wounds were not real they were never injured as the ghosts created illusion to make their wounds look and feel real as long as they believe in their situation. As Mulder and Scully left the house, Maurice and Lyda watched and claimed that Mulder and Scully were better than they thought as they escaped and the ghosts' plans were not fulfilled. Once the agents left, Maurice and Lyda decided to spent Christmas together as they have always done and always will.