This story begins with the most innocent of domestic scenes. Mary Maloney, a housewife in her sixth month of pregnancy, is waiting for her husband to return home. It is a Thursday night, and they usually eat out. When Patrick Maloney does come home, he is strangely moody and takes a stronger drink than usual. Mary tries to divert him with the usual domestic comforts but to no avail. Patrick asks her to sit down, announcing that he has an important matter to discuss with her. Though the reader is never told, it is clear that Patrick is going to divorce Mary. He ends his speech by saying that he will see that she is provided for and that he hopes that there will be no fuss because it might reflect badly on his position in the police department.
The announcement that she will lose the man around whom her world revolves puts Mary into a daze of unbelief. Instead of arguing with Patrick, she goes on as if nothing has happened, hoping that this will somehow cause her problem to go away. She prepares to make supper and goes down to the deep freezer. She chooses a frozen leg of lamb for the meal. Moving like a somnambulist, she walks into the living room. When Patrick tells her that he does not want dinner, Mary moves behind him and hits him over the head with the leg of lamb.
Patrick falls to the floor with a crash, and this brings Mary to her senses. Mary realizes that she has killed Patrick, and though she is willing to take the legal consequences, she fears for her unborn child, who might die if she is executed. Her mind is now working clearly, and she devises an elaborate deception for the police. She prepares the leg of lamb and puts it in the oven. She then goes to her room and gets ready to go out. As she does so, she rehearses the conversation that she will have with the grocer, trying to get the voice tones and facial expressions as close to normal as possible. This deception is put into operation. She goes to the grocery and uses the exact words that she has rehearsed, so that the whole scene at the grocery appears to be the everyday act of a wife picking up food for her husband’s dinner and chatting with the grocer. She then returns home, telling herself that she must remain natural and to expect nothing out of the ordinary when she enters the house. Thus, when Mary does arrive, she calls out to Patrick as if he were still alive. Her shock at actually finding Patrick’s body is almost completely unfeigned, as if she really did not know that she has already killed him.
Mary then calls the police and reports that Patrick Maloney has been killed. Two police officers, one of whom is Jack Noonan, arrive at the house. Both men are familiar to Mary, who knows most of Patrick’s friends on the police force. They begin the investigation into Patrick’s murder by recording Mrs. Maloney’s story about going out to get food for supper and coming back to find Patrick’s body. Noonan, completely taken in, comforts Mary, asking if she would rather go to her sister’s house or stay with his wife. Mary, however, stays throughout the investigation. When a doctor and other specialists arrive to examine the body, the police conclude that Patrick was killed by a blow to the head with a blunt instrument, probably made of steel.
The police begin searching the house for the murder weapon but with no success. Mary asks Noonan for a drink, then invites him to have one himself. Soon all the police are having a drink, and the investigation has become a consolation scene. Finding that the lamb is now cooked, Mary asks the police officers to eat it because she owes it to Patrick to extend the hospitality of his home to his friends. She finally persuades them to eat the meal as a favor to her. As they do so, they remark that the murder weapon would be very difficult to conceal. One man says to Noonan that the weapon is “probably right under our very noses,” which causes Mary to giggle.
In “Lamb to the Slaughter,” Dahl shows his mastery of short-form psychological horror, in which the very absence of overtly fantastical elements only accentuates the building atmosphere of horror. The entire story takes place within the apartment of one Mary Maloney, pregnant wife of a loutish and incompetent police detective. Hers has been a steadfastly domestic existence, and she has ignored her husband’s misbehavior until one night, when he comes home late after yet another round of drinking and informs her that he is going to leave her for another woman. Still she clings to her illusion of happy domesticity, telling him she will fix supper.
Only when he sneeringly tells her not to bother with supper does she snap and bludgeon him with the frozen leg of lamb that was to have been their meal. After the initial fit of anger, she comes back to her senses and realizes what she has done. Not wanting to ruin the life of the baby she is expecting, she puts the leg of lamb into the oven and goes to the grocery store to get some vegetables. While there, she makes a point of talking cheerfully with the grocer about fixing her husband’s supper.
Upon returning to their apartment, she screams in horror and makes a great commotion at finding her husband’s body lying on the floor. She then calls the police, and within the hour they are investigating. Agreeing that he was killed by a heavy, blunt object, they begin a search for the murder weapon and are quite puzzled at being unable to find it. After a few hours, Mary comments that she had forgotten to turn the oven off in all the confusion and suggests that the officers might wish to eat the now-cooked leg of lamb. Without a second thought they all set to eating and discussing the case, never realizing that the meat they are avidly devouring is in fact the missing murder weapon. Meanwhile, Mary sits in the living room and giggles softly to herself in amusement at the way in which she has tricked the police.
The ending is particularly striking because it so blatantly violates the expectation of the murder mystery, namely, that the culprit should be caught at the end. Yet at the same time there seems to be a certain justice in Mary’s not being caught, that she was in fact justified in taking the life of a man so loutish as to not only betray his wife by dallying with another woman but also to abandon his wife when in the vulnerable state of pregnancy, thus also abandoning his unborn child.