April 1964, but spring hasn't quite sprung. The bad weather seems suited to nothing but bad news. And bad news is coming to the police station. First, Bordelli's friend Casimiro, who insists he's discovered the body of a man in a field above Fiesole.
Bordelli races to the scene, but doesn't find any sign of a corpse.
Only a couple of days later, a little girl is found at Villa Ventaglio.
She has been strangled, and there is a horrible bite mark on her belly.
Then another little girl is found murdered, with the same macabre signature. And meanwhile Casimiro has disappeared without a trace. The investigation marks the start of one of the darkest periods of Bordelli's life: a nightmare without end, as black as the sky above Florence.