An unnamed protagonist chooses to spend the night in an allegedly haunted room in Lorraine Castle. He intends to disprove the legends surrounding it. Despite vague warnings from the three infirm custodians who reside in the castle, the narrator ascends to "the Red Room" to begin his night's vigil. Initially confident, the narrator becomes increasingly uneasy in the room. He attempts to conquer his fear by lighting candles, but keeping the candles lit in the draughty room becomes an ongoing battle. They are eager to hear a description of the phantom, but he surprises them by explaining that there is no ghost residing in the room. The room is haunted by fear itself.
For many years the protagonist and his uncle, Dr. Elihu Whipple, have nurtured a fascination with an old, abandoned house on Benefit Street. Dr. Whipple has made extensive records tracking the mysterious, yet apparently coincidental sickness and death of many who have lived in the house for over one hundred years. They are also puzzled by the strange weeds growing in the yard, as well as the unexplained foul smell and whitish, phosphorescent fungi growing in the cellar.
Drawing of a man leaving an open door in a house, inset into a drawing of a naked man cowering among plants, apparently recoiling from the inset picture. After the protagonist discovers a strange, yellowish vapour in the basement, which seems to be coupled with a moldy outline of a huddled human form on the floor, he and his uncle decide to spend the night in the house, investigating the possibility of some supernatural force. They set up cots and chairs in the cellar, arm themselves with military flamethrowers, and outfit a modified Crookes tube in the hopes of destroying any supernatural presence they might find.
In the isolated, desolate, decrepit village of Dunwich, Wilbur Whateley is the hideous son of Lavinia Whateley, a deformed and unstable albino mother, and an unknown father (alluded to in passing by mad Old Whateley, as "Yog-Sothoth"). Strange events surround his birth and precocious development. Wilbur matures at an abnormal rate, reaching manhood within a decade. Locals shun him and his family, and animals fear and despise him (due to his odor). All the while, his sorcerer grandfather indoctrinates him into certain dark rituals and the study of witchcraft. Various locals grow suspicious after Old Whateley buys more and more cattle, yet the number of his herd never increases, and the cattle in his field become mysteriously afflicted with severe open wounds.