The corpse of a man with his throat cut bobs on the waves of a Venetian canal at the foot of a marble staircase. A Venetian couple adopts a baby born to an illegal immigrant. A wealthy widow is looking for choir boys to perform the works of Henry Purcell. A famous lawyer defends a fraudster from art. An unknown Albanian philanthropist terrorizes the owner of a network that supplies prostitutes via the Internet. All these events are intertwined into a mysterious case, which will be dealt with by Commissioner Alvisio Campana, which neither criminals nor women can resist. Everything would be fine, but the commissioner lives in a dilapidated palazzo under the same roof with his sister and two uncles. This eccentric trio, obsessed with ancient lampshades, painting masterpieces that have floated out of nowhere, and finding harmony with the world, constantly interferes in his affairs. Dismissing advice prompted by their artistic intuition, the pragmatic commissioner prefers to conduct an investigation based on dry facts. However, solving the puzzle will require the participation of all members of the Campana family. And they are the original Venetians and know very well that after the floods the waters of their native lagoon always became cleaner.