The Rats in the Walls recap

After his son's death, an American named Delapore restores Exham Priory, the English seat abandoned by his family after an ancestor murdered his household. Delapore and his cat begin hearing rats inside walls where no rats can be found. An investigation uncovers a passage beneath the priory leading to an enormous complex used across many centuries by the de la Poer family. The remains show that its inhabitants bred human captives for food and ritual. The discovery breaks Delapore's composure; following the sound of rats, he attacks and consumes part of his friend Captain Norrys while reverting through languages associated with his ancestry. Confined afterward, he continues to hear rats behind the walls of his cell.

An American named Delapore, grieving the death of his only son Alfred, buys and restores Exham Priory, the ruined English home of his ancestors. The surrounding community still fears the de la Poer family because Walter de la Poer murdered his household centuries earlier and fled to America. Soon after moving in, Delapore's cat begins following sounds inside the walls. Delapore eventually hears masses of rats as well, though servants and visitors detect nothing. He also dreams of an underground cavern where a herdsman drives human beings like animals. Captain Edward Norrys, a friend of Alfred and now of Delapore, helps investigate. They find evidence that the priory rests over much older construction, and an expert party opens a concealed route below the building. The explorers descend into a vast complex containing structures from several historical eras, along with pens, butchered human bones, and remains altered by generations of captivity. The evidence shows that the de la Poers maintained a hidden society that treated captive people as livestock and food. Overwhelmed by the discovery and again hearing the rats, Delapore runs into the darkness. His companions find him over Norrys's body, speaking in increasingly ancient languages after killing and partly consuming his friend. Delapore is committed to an institution while authorities suppress the underground findings. He denies conscious responsibility and continues to hear rats moving behind the padded walls of his room.

The expedition follows the hidden passage beneath Exham Priory into a vast complex where generations of the de la Poer family kept people as livestock and practiced cannibalism. Confronted by the evidence, Delapore hears the rats again and runs deeper into the caverns. His companions later find him crouched over Captain Norrys's body, having killed and partly eaten his friend while speaking in a succession of older languages. He is confined in an institution, and the official account attributes Norrys's death to him and conceals much of what lay below the priory. Delapore insists that the rats drove him to the killing. From his padded room he still hears them moving inside the walls, leaving uncertain whether they are supernatural pursuers, the sound of ancestral madness, or both.