When Maria Grazia Battestini, as wealthy as she is bad-tempered, is discovered brutally murdered in her apartment, there are no friends or family who come to mourn her. Her housekeeper, who has disappeared, rapidly becomes the prime murder suspect; she is arrested while trying to return to Romania, and in her attempt to escape custody is hit by a train. She had been carrying a large sum of money and false papers – an open-and-shut case for Tenente Scarpa, who is standing in for Brunetti during the latter's vacation. His superior, Patta, is also pleased that the case can be filed away so promptly. Brunetti, however, is not so sure. Having returned from Ireland, he begins an unrelenting search for the true perpetrators of the crime. But no matter how he puts the pieces of the puzzle together, they refuse to form a complete picture. Until Paola reminds him of the Bible and the seven deadly sins, which have today all but been forgotten. With the help of Vianello and Elettra, and ignoring all of the rash conclusions which have been previously drawn, he unearths the secret motives that led to the old lady's death.