Marjorie had never seen a dead body until she got home one tranquil summer evening and found her sister Dot lying on the kitchen floor in a pretty dress, with her head in the oven. She looked peaceful, as if she was asleep. Their mother suspects, however, that Dot's death was far from natural. What's more, she knows who the killer is – and she is determined to make him suffer. So slowly and meticulously, she plots her revenge. After all, who would suspect a neatly dressed, grey-haired widow of anything? And what could possibly go wrong?