To help promote tourism, the Grand Duchy of Allemonde begins offering a winter opera program in addition to its long-established summer festival. But when a young girl is murdered, and Wilfred Beck, the opera theatre's set designer, is repeatedly threatened, it's up to Chief Inspector D. T. Giovanni and his team to discover who's causing the mayhem. A bewildering array of suspects, a fierce debate over gender identity, and not one, but two secret societies combine to make Giovanni's latest challenge a mystery on an operatic scale.