Tuscany. Winter, 1540. Travelling north into the hills above Florence, investigator Cesare Aldo seeks answers about his past.

The trail leads him to Ospedale de' Pazzi, a secure institution for the criminally insane. Soon after arriving a blizzard engulfs the area, trapping Aldo and his companion, Doctor Saul Orvieto. Even more alarming, their cart driver is found dead.

It looks like he fell over a nearby cliff in the whiteout – but Aldo suspects foul play. When a brutal slaying occurs in the central courtyard, it becomes clear a killer lurks among them. With the snowstorm sealing everyone in and a murderer hunting fresh victims, Aldo’s search for the truth proves deadlier than he could ever have imagined.