In this episode Marty contacts a phony psychic medium who claims to be able to contact the dead husbands and wives of well heeled middle aged widows and widowers. To the fake medium's extreme surprise he is then able to materialise as a ghost in front of her (the first real ghost she has ever seen in her long career) and gets her to confess to receiving money from the gang of three middle class men in return for setting up seances at which they target wealthy widows and lure them to their deaths. She shows a genuine sense of fear and remorse over her wrong-doing when confronted by Marty the ghost.
This is a particularly macabre episode (very different from the almost slapstick comedic atmosphere of The Ghost of Monte Carlo) with the sudden unexpected grisly death of the widow in and air-tight toom, initially masquerading as a delightful cottage drawing room or study (the room that gives its name to the episode title), shown in graphic detail at the start of the program. Only later on in the episode does it become clear why such a bizarre and elaborate means of murdering the widows has been constructed by the script writers when Jeff is also nearly gassed to death in the same room only to be saved at the last moment with Marty's usual spiritual assistance.