‘‘Lamb to the Slaughter’’ demonstrates Dahl's ability to reflect aspects of human perversity, cruelty, and violence in adult fiction. His presentation features a cynically detached narrator, and elements of black comedy. The horror of this story prefigures the grotesqueness seen in the author's later work for children, including James and the Giant Peach and Charlie and the Chocolate Factory.
In shock at the news, and seemingly in a trance, Mary fetches a large leg of lamb from the refrigerator to cook for their dinner. Then Mary gets told to stop the routine and not make him dinner, and she snaps, bludgeoning Patrick in the back of the head with the frozen lamb leg, killing him. After pacing the room, Mary realizes that she must conceal her crime. She prepares the leg of lamb and places it in the oven. Then, after practicing a cheerful routine, she heads out to the store to buy some vegetables for her roast. When she gets back, she enters the room where she killed her husband and calls the police.
When the police arrive, they question Mary and survey the scene. The police come to the conclusion that Mary's husband was killed with a sledgehammer. The police then search the house and surrounding area for the murder weapon. After a fruitless search, the police realize that no one has turned off the oven. Mary offers all the policemen the cooked leg, asking them to accept her hospitality, and they accept. When the lamb is nearly finished, the police facetiously discuss the possibility of the murder weapon being right under their noses. Upon hearing the officers' facetious remarks, Mary laughs slyly to herself at the irony.