Mardi Gras, Carnival, the season of parties and parades leading up to Lent. Not even the newly enacted Prohibition could dampen the spirits of the people of New Orleans. But one figure is on everyone's mind, the Midnight Masquer, the mysterious bandit who appears at the stroke of midnight in the costume of an aviator to rob wealthy party goers of their jewels and money. Is he a criminal, or just a joker? The question is up in the air until, on the last night of carnival, things turn tragic and one of New Orleans leading citizens is murdered at the hand of the bandit. But was it the real Masquer or an imposter that pulled the fatal trigger? And, despite the fact that he was discovered moments later in an aviator's suit, the son of the murdered man claims that he is innocent of the crime. Nothing is as it seems, as Henry Gramont's Mardi Gras turns into a web of deceit, high stakes oil prospecting, and organized crime.