Rome, 1650.
The streets are teeming as thousands of pilgrims flood in for the Holy Jubilee, but behind the gilded facade of the Vatican, power is unravelling.
Donna Olimpia Maidalchini has long kept Pope Innocent X under her thumb, but as loyalties shift, her enemies close in. And her most dangerous opponents may be those she deems too weak to matter.
Two destitute nuns arrive, fleeing the ruined city of Castro and each carrying secrets that could destroy them.
Meanwhile, the assistant to the famed Spanish artist Diego Velazquez is drawn into a perilous conspiracy - one that could bring Italy to its knees, and against which his own desperate ambitions seem to count for nothing.
As the sweltering summer heat rises, survival, not salvation, becomes the ultimate goal - and in this world of sin, saints almost never survive.
