The Rats In The Walls by H. P. Lovecraft

In this chilling tale, a man named Delapore returns to his ancestral home in England, only to uncover a series of horrifying secrets buried beneath the estate. As he delves deeper into the history of his family and the ancient structure, he is drawn into a nightmarish world of madness and terror. The story masterfully weaves themes of ancestral guilt and the thin veneer of civilization, culminating in a terrifying revelation that blurs the line between sanity and insanity.