When the play they are attending is interrupted by a policeman yelling at everyone to stay where they are and not get out of their seat, most of the audience in the Roman Theater think nothing of it. After all, the play is about the underworld and the police, and has been full of the sounds of sensationalized criminal society. But this policeman isn’t part of the play; someone in the audience has been murdered.

Inspector Richard Queen soon arrives on the scene, closely followed by his son Ellery, a mystery writer who often assists Richard on his cases. They quickly determine the victim was a well-known crooked lawyer, and discover an odd clue: the man’s top hat is missing. That clue will loom large as the Queen’s investigation leads them deeper into both New York high society and the criminal world in which the dead man moved.

The Roman Hat Mystery is the first of the Ellery Queen detective novels . Ellery Queen is the pseudonym of a pair of cousins who wrote most of the novels, as well as the name of their fictional amateur detective.