The story is set in the city of Paris, France, in the mid-nineteenth century.

The particularly brutal murders of a woman and her daughter have stumped the police. A young man of noble birth but of diminished financial means, Auguste Dupin decides after reading about the crime in the newspapers that he can solve what the police cannot. As a result, the physical setting of the story is less important than its mental setting—the mind of Dupin. There is little overt action in the story; the details of the crime itself are all derived from newspaper accounts. The solution of the crime requires no overt action, but, as has become the tradition of the detective story, is an armchair process whereby the detective recounts the events of the crime as he has deduced them from the available clues.