One of the major themes of Roald Dahl’s “Lamb to the Slaughter” is that appearances can be deceiving. The story opens on what appears to be a scene of domestic bliss. Mary Maloney is six months pregnant and eagerly awaits her husband’s return from work.
"Now and again she would glance up at the clock, but without anxiety, merely to please herself with the thought that each minute gone by made it nearer the time when he would come.”
The appearance of a happy home is utterly shattered, however, when Mary’s husband abruptly announces that he wants a divorce. The reader instantly sympathizes with Mary, who appears to have been too blindly devoted to her Patrick to realize what was coming. Mary’s initial reaction is one of utter shock. Seemingly unable to even process what her husband has told her, she begins preparations for dinner, absentmindedly grabbing a leg of lamb from the freezer. When her husband rudely tells her not to bother with dinner, Mary snaps and clubs him over the head with the frozen leg of lamb.
“At that point, Mary Maloney simply walked up behind him and without any pause she swung the big frozen leg of lamb high in the air and brought it down as hard as she could on the back of his head."
To her husband, Mary Maloney probably seemed incapable of standing up for herself, and his belief in her devotion and weakness led him to drastically underestimate what she was capable of. Though she initially appears to be the metaphorical “lamb” of the title, she forcefully reverses roles and transforms Patrick into the unsuspecting victim.
The themes of appearance and deception are further explored as Mary attempts to get away with the murder. After quickly realizing that she needs an alibi, she attempts to compose herself before going out.
"Then she washed her hands and ran upstairs to the bedroom. She sat down before the mirror, tidied her hair, touched up her lips and face. She tried a smile. It came out rather peculiar. She tried again."
It’s clear that Mary understands her femininity to be her greatest asset in avoiding suspicion. Though her docile and cheerful disposition seemed to come naturally before, we see her deliberately practice it in the mirror. Her carefully crafted performance is a success and she is able to establish an alibi at the grocery store. She appears to all the world as her normal devoted self, even speaking to a clerk about what she will cook her husband for dinner.
"No, I’ve got meat, thanks. I got a nice leg of lamb, from the freezer." "Oh." "I don’t much like cooking it frozen, Sam, but I’m taking a chance on it this time. You think it’ll be all right?"
This scene is full of dramatic irony as Mary casually discusses cooking what the reader knows to be her murder weapon. Her ability to nonchalantly speak about it further illustrates the depth and skill of her deception. Her crafted persona continues to be of use as she convincingly plays a devastated wife to Patrick’s fellow police officers. The police quickly dismiss her as a suspect, in part because of her alibi and in part because she does not conform to their expectations of a cold-blooded killer. As she fusses over them, they discuss the peculiarities of the case, completely blind to the real identity of the murderer. In fact, their discussion betrays their unconscious assumption of a male suspect and reveals that suspicion of a woman doesn’t come naturally to them.
"It's the old story," he said. "Get the weapon, and you've got the man."
Ultimately, we see that Mary has successfully used her femininity to craft a false narrative. She takes care to present herself as innocent and, thus, is able to deceive everyone. Though it is easy to say that it was Mary’s cunning and deviousness that allowed her to get away with the crime, it’s important to note that she only succeeds because the people around her are so blinded by superficial appearances.