The story begins with visual imagery highlighting the warmth and cozy atmosphere of Mary's home. Her own feelings are described as tranquil, content, and hopeful. She looks forward to her husband's arrival home with great anticipation.
She loved to luxuriate in the presence of this man, and to feel-almost as a sunbather feels the sun-that warm male glow that came out of him to her when they were alone together. She loved him for the way he sat loosely in a chair, for the way he came in a door, or moved slowly across the room with long strides.
Mary's feelings about her husband indicate that her worship of her husband is absolute and total in its trust. So, when he informs her that he is going to leave her, her first sentiments are that of incredulity and denial. It is obvious that Mary had never expected to be the recipient of such devastating news. Earlier in the story, the author mentions that Mary is six months pregnant, so the disastrous news that her husband has found another woman almost incapacitates her. She is in shock and resorts to the comfort of routine in order to process her new precarious situation; slowly, as if in a trance, Mary prepares to make her husband dinner. She takes out a leg of lamb.
She couldn't feel anything at all- except a slight nausea and a desire to vomit. Everything was automatic now-down the steps to the cellar, the light switch, the deep freeze, the hand inside the cabinet taking hold of the first object it met.
However, her husband's rough and insensitive refusal evinces an instantaneous and visceral reaction in her. She instinctively brings the frozen leg of lamb down on her husband's head.
Interestingly, the author tells us that, after killing her husband, Mary's thoughts become clearer. The stimulus of one emotional, spontaneous act awakens Mary's senses and maternal instincts. Now, her thoughts and feelings turn towards protecting the future of her child. Without delay, Mary refers to her years as the wife of a detective to help her concoct a plausible alibi. She practices careful and natural responses before she orders vegetables and a cheesecake dessert from the grocer. By allowing the grocer to wait on her, Mary knows that he will later substantiate her story when the police question him.
Mary then walks home to 'discover' the body of her dead husband. She allows herself to give way to her grief before calling the police; her grief is as natural as it is cathartic. She has just killed the man she once loved deeply; Mary knows that she must play the part of a distraught wife to perfection is she is to escape prosecution for her crime. As a strategy, Mary allows her natural, feminine expressions of grief to lull the detectives into security. She cleverly presents herself as the innocent and vulnerable widow who has been dealt a cruel hand by the vagaries of fate.
As a stroke of genius, Mary offers the men whiskey, further dulling their senses and disarming their instincts. The men drink in order to further avoid disappointing the 'fragile,' grieving widow. Mary also serves the leg of lamb to the detectives. In everything, she manages to cater to the male desire for domestic comfort and hospitality. While the men enjoy the leg of lamb, Mary giggles to herself: the detectives are eating forensic evidence as well as the murder weapon.