At a dinner party given by his parents-in-law, Commissario Brunetti meets Franca Marinello, the wife of a prosperous Venetian businessman. He's charmed - perhaps too charmed, suggests his wife Paola - by her love of Virgil and Cicero, but shocked by her appearance.

A few days later, Brunetti is visited by Carabinieri Maggior Filippo Guarino from the nearby city of Marghera. As part of a wider investigation into Mafia takeovers of businesses in the region, Guarino wants information about the owner of a trucking company who was found murdered in his office. He believes the man's death is connected to the illegal transportation of refuse - and more sinister material - in his company's trucks. No stranger to mutual suspicion and competition between rival Italian police departments, Brunetti is nevertheless puzzled by the younger man's behaviour.

Eventually Guarino agrees to email a photo of his suspect, but by the time the photograph arrives, he himself is dead. Was he killed because he got too close? And how is it that Franca Marinello is involved?