Florence, 1943. Two sisters, Isabella and Caterina Cammaccio, find themselves surrounded by terror and death; and with Italy trapped under the heel of a brutal Nazi occupation, bands of Partisans rise up.

Soon Isabella and Caterina will test their wits and deepest beliefs as never before. As the winter grinds on, they will be forced to make the most important decisions of their lives. Their choices will reverberate for decades.

In the present day, Alessandro Pallioti, a senior policeman agrees to oversee a murder investigation, after it emerges the victim was once a Partisan hero. When the case begins to unravel, Pallioti finds himself working to uncover a crime lost in the twilight of war, the consequences of which are as deadly today as they were over sixty years ago.