The story begins with Mary Maloney faithfully waiting for her husband Patrick to come home from his job as a detective. Six months pregnant and happy in her marriage, she eagerly watches the clock while she sews. When Patrick arrives, she is ready to hang up his coat, prepare a drink for him, and sit in silence with him as he rests. For Mary, who is alone in the house during the day, this after-work ritual is one she looks forward to. However, as Mary attempts to care for her husband, Patrick brushes off her efforts, drinks more than usual, and declares that he has something to tell her. While a nervous Mary scrutinizes him, Patrick tells her that he is leaving her. Though the narrator leaves out the details, it becomes clear that Patrick still plans to take care of her financially but that their marriage is over. Mary, who is in disbelief, decides to act as if nothing has happened and fetches a frozen leg of lamb from the cellar to prepare their supper. When Patrick tells her not to bother and begins to leave, Mary suddenly swings the frozen meat at the back of Patrick’s head and kills him.
Once Mary realizes that her husband is dead, she thinks rapidly of how to protect herself and thus her unborn child from the penalty of murder. She puts the meat into the oven, and while it begins to cook, she practices her expression and voice, and then goes out to a nearby grocery store and chats amiably with Sam, the grocer, about what she needs to buy for her husband’s dinner. On her way home, she purposefully acts as if everything is normal, and then is shocked to “discover” Patrick’s body on the floor and begins to cry. Distraught, she calls the police, and two policemen, Jack Noonan and O’Malley, friends and colleagues of Patrick, arrive. Mary, maintaining her façade, claims that she went out to the store and came back to find Patrick dead. As other detectives arrive and ask her questions, her premeditated chat with Sam is revealed to be her alibi and she is able to elude suspicion.
The policemen sympathize with Mary and attempt to comfort her. Despite Sergeant Noonan’s offer to bring her elsewhere, Mary decides to stay in the house while the police search for the murder weapon. Jack Noonan reveals to Mary that the culprit probably used a blunt metal object and that finding the weapon will lead to the murderer. After nearly three fruitless hours of searching in and around the house for the weapon, the policemen are no closer to finding the murder weapon and never suspect that it could be the frozen meat cooking in the oven. Mary is able to persuade the tired, hungry, and frustrated policemen to drink some whiskey and eat the leg of lamb that by now has finished cooking. As the men eat the evidence in the kitchen, Mary eavesdrops from another room, giggling when one of the men theorizes that the murder weapon is “right under our very noses.”
