Mary Maloney, a pregnant housewife patiently waits for her husband to return home from work. It is Thursday night, and they usually go out to eat for dinner.
After returning home and refusing many things Mary offers, Patrick breaks the news to Mary. He tells her that he wants a divorce and that she will be provided for. Mary refuses to believe what her husband just told her and goes downstairs to get a lamb leg for their dinner. He refuses her offering and tells her that he is going out.
Refusal from Patrick angers Mary. She moves behind him and hits him on the head with the leg of the lamb which kills him. She understands the consequences of her action and fears for her unborn child. She thinks of a deceptive plan for the police by putting the lamb in the oven and gets ready by working on her facial expression and tone of voice to use at the grocery store.
Pretending as nothing out of the ordinary has happened, Mary buys some vegetables and dessert to go with the dinner for her husband. She succeeds in establishing normalcy at the grocery store and returns home.
When Mary returns home, she reacts to the dead body of her husband and calls the police to report the murder. The policemen arrive and investigate the scene concluding that the death is due to a blow on the head with a blunt item. However, they are unable to find the murder weapon.
After a while, Mary suggests the police officers take a rest and have a drink and states, "it is what Patrick would have wanted". She then persuades them to eat the cooked lamb leg that she had used to kill her husband. While eating the lamb leg the officer comment that the weapon is "probably right under our very noses", she quietly giggles in the living room.