As a favour to his wealthy father-in-law, the Count Falier, Commissario Guido Brunetti agrees to investigate the seemingly innocent wish of the Count's best friend, the elderly and childless Gonzalo, to adopt a younger man as his son. Under Italian inheritance laws, this man would become the sole heir to Gonzalo's substantial fortune, something which Gonzalo's friends, including the Count, find appalling. For his part, Brunetti wonders why they're so intent on meddling in the old man's business.

Not long after Brunetti and Gonzalo meet, Gonzalo passes away. Old and frail, his death goes unquestioned, until one of his closest confidantes is strangled in her hotel room after sending an email about the adoption. To find the killer and solve a murder most foul, Brunetti must rely on his instincts which lead him to untangling long-buried secrets from Gonzalo's past.