The walls of the Whateley farmhouse are gone, the prints in the road are the size of barrel-heads, and whatever has been growing in the dark for fifteen years is now moving through the Massachusetts countryside unseen. H. P. Lovecraft's The Dunwich Horror reaches its conclusion as Dr. Armitage decodes a diary that nearly breaks him, and three scholars from Miskatonic University ascend Sentinel Hill alone to face something that called out for its father in a voice no human throat could produce. The hills of Dunwich still shake sometimes — and the vegetation on Sentinel Hill has never been right since.

Something was born in Dunwich, Massachusetts on Candlemas 1913, and the hills shook all night before it arrived. H. P. Lovecraft's The Dunwich Horror begins with the Whateley bloodline — the cursed landscape, the sealed farmhouse, the thing being fed in the dark behind boarded walls — and the boy who was never entirely human growing faster than any child should. By the end of Part One, Wilbur Whateley is gone; what he was raising in that upper room is not.

An American man restores his ancestral English priory, only to discover his cats are responding to sounds within the walls that no human can hear — the impossible scurrying of rats moving downward through solid Roman stone. Investigating beneath the deepest sub-cellar, he and a team of scholars uncover a vast underground grotto containing millennia of human bones, stone pens where debased half-human creatures were kept and fattened, and pits where rats had feasted on them for generations. The horror culminates in the darkness of the cavern when the narrator, driven mad by the ancient bloodline awakening within him, is found crouching over the half-eaten body of his companion — and insists from his barred room at Hanwell that it was the rats, the rats in the walls.