The whodunnit is a subgenre of crime fiction focused on the puzzle of a crime. A crime is committed by one of a limited circle of suspects, each with a motive and something to hide. The story typically unfolds in a closed, often idyllic setting such as a country manor, a remote island, or a stranded train.
The plot then follows the investigation, led often by an amateur detective, who gathers clues and interviews suspects. Information is gradually revealed, leading to a climactic final gathering where the detective explains the "how" and, crucially, the "who" behind the "dunnit." The appeal lies in the promise of a fair play resolution, where all clues are available to the reader, allowing them to match wits with the detective and be surprised by a solution that was hiding in plain sight all along.
The genre is exemplified by the novels of Agatha Christie, and modern interpretations include the Knives Out productions and the BBC series, Death in Paradise.