The Book of Secrets by Anna Mazzola

Months after the plague ravaged Rome, men are still dying in unnatural numbers, and rumour has it that their corpses do not decay. The Papal authorities commission lieutenant governor Stefano Bracchi to investigate as subtly as he can.

Meanwhile, to the north of the city, Anna Maria Aldobrandini, Duchess of Cesi, is trapped in an abusive relationship with a much older man she was made to marry when she was only a girl. Her friend, Sulpizia Vitelleschi, is in a similar position, but there is no prospect of divorce or escape. To the south, Cecilia Verzellina fears that, once her jealous son-in-law is released from prison, he will kill her beautiful daughter.

Bracci's investigation at the Tor di Nona will introduce him to horror, magic and an unthinkable discovery. And he begins to wonder: should certain deeds should remain forever unpunished...