A very important letter is taken from Paris' Royal Palace. Although the thief's identity is known, the police are unable to locate the location where the accusatory letter is concealed. In an effort to find out where it is, the Prefect of Police asks C. Auguste Dupin for assistance. The third of Edgar Allan Poe's three detective tales starring the Frenchman C. Auguste Dupin is a short story titled "The Purloined Letter." The other two are "The Murders in the Rue Morgue" and "The Mystery of Marie Rogêt."