The Man Who Was Poe by Avi is a thrilling fictional novel, encasing the story of a boy who has lost his family mysteriously and a disguised author who assists the boy through his journey towards finding them. The book is set in Providence, Rhode Island during 1848 where an 11-year-old boy named Edmund Brimmer and his twin sister "Sis" live with their aunt Pru in a run-down tenement. The story begins when Edmund leaves his sister alone to reach the market, being in desparate need of food since Pru, unusually, hadn't returned from her vacation yet. When Edmund returns with the food, Sis is nowhere to be found, although Edmund promises he had locked the door.
Shortly afterwards, a poor man who's name is supposedly Auguste Dupin arrives at the tenement, having nowhere else to sleep. Edmund agrees to his stay, but makes a deal with Dupin entailing his mandatory duty in solving the mystery of Edmund's lost family. The first key clue is revealed when the murder of Pru is announced and investigated. Edmund is stricken by this, but still believes Sis is alive, although Dupin highly doubts it. Later, Auguste investigates the town bank that has been very recently robbed, and finds a pearl button in a hidden shaft matching Sis' shoes. The next button, identical to the first, is found in a mausoleum inside the cemetery. Also serving as a progression to the mystery, Edmund picks up a dropped code that reads: "Meet me at the hotel. I have moved girl and gold. Must leave. Sunrise at six A.M." In addition, he is confronted with a long stare from a man who is very familiar, but undefinable, to Edmund. Following this encounter, another strangely familiar man with white hair stocks Edmund, but the boy is able to escape and hide.
Marking the climax of the story, Dupin reveals that his true identity is Edgar Allen Poe, a very well-known author, and that the name "Dupin" was taken as a disguise name from one of his books. After this confession, Poe thoughtfully pieces together the mystery. Edmund learns through Poe that the familiar man that had stared at him was his stepfather, Mr. Rachett, who had recently abandoned Edmund's mother, which led to Pru taking custody of the children. Rachett had been in cahoots with Petersen, the white-haired man, and together they had robbed the Providence bank and abducted all three of Edmund's family members. Since Pru and Edmund's mother were twins, Pru had tricked the men into killing her instead of the mother so she could be reunited with her children. When Edmund finds this out, he locates his mom at a church and brings her home. In response to the secret note they had found earlier, Edmund, Poe, and Throck (the night watchman), set sail to capture the two criminals aboard the Sunrise and end up saving Sis. Edmund and his mother are relieved, but Poe didn't want Sis to live in "his story" that he had been writing, because he explains to Edmund in conclusion that his own life had been parallel to Edmund's, with the exception of his "Sis" ' tragic death.
