An unknown narrator describes a meeting with a man named Auguste Dupin. They were in a bookstore in London both in search of same book. Soon after they became roommates. Narrator describes Dupin as a genius when it comes to his detective skills.
The roommates were walking together one night where they then read newpaper headlines about murders in the Rue Morgue. Two victims Madame L'Espanaye and her daughter both murdered. There was still 4,000 Francs in house so money wasnt a motive.
With the evidence found at the scene police arrested a suspect name Le Bon, Dupin knew Le Bon. This sparked his interest to work with the case. Dupin looked closer into the scene and finds clues that lead to an nonhuman creature to commit the crime.
Due to the circumstances on how the murders were committed and clues such as the criminal coming through a high window, nonhuman hair particle, and lastly paws that choked the daughter. Dupin came to a conclusion that an Orangutan is the culprit.
Dupin tracks down a sailor who he believes is the Orangutans owner. He puts the sailor at gunpoint and demands information. Sailor cracks and reveals that he watched his pet commit the murders.