Poe gifts us with another mystery in "The Gold Bug," a brilliant blend of folklore and fiction. But he decides to leave his frequent protagonist Detective Dupin in the dust, instead deploying southerner William Legrand to unravel the puzzle at hand.
In what's basically a buried treasure story, Legrand finds the titular gold bug, a scaraboeus, and is soon after bitten by the creature. Still, he's convinced it will lead him to the desired bounty and emphatically expresses this to his servant Jupiter, who thinks the scarab has poisoned his mind to the point of insanity. We're convinced, too, until Legrand solves an elaborate cryptogram (to which Poe owed much of the story's success; liken it to the modern day Soduku craze), which leads him to serious bundle of cash.
Ironically, "The Gold Bug" earned Poe the most money he earned in his lifetime, $100 for a three-part-installment in the Philadelphia Dollar Newspaper (double irony!).