In the degenerate, unliked backwater of Dunwich, Wilbur Whately, a most unusual child, is born. Of unnatural parentage, he grows at an uncanny pace to an unsettling height, but the boy's arrival simply precedes that of a true horror: one of the Old Ones, that forces the people of the town to hole up by night.
A Providence, Rhode Island resident teams up with his beloved, antiquarian uncle in studying why a decrepit 18th century house has been left vacant for so long. It appears that anyone who lives in the house long enough goes crazy and/or wastes to death. Of course, our protagonists decide to spend an evening in the cellar of the house...