H.P. Lovecraft 
The Rats in the Walls [EPUB ebook] 

Set in 1923, ‘The Rats in the Walls’ is narrated by the descendant of the De la Poer Family, who has moved from Massachusetts to his ancestral estate in England, the ruined Exham Priory. To the dismay of nearby residents, he restores the Priory. After moving in, the protagonist, and his cat, frequently hear the sounds of rats scurrying behind the walls. Upon investigating further and through recurring dreams, he learns that his family maintained an underground city for centuries, where they raised generations of ‘human cattle’—some regressed to a quadrupedal state—to supply their taste for human flesh..