Every August, Florence shimmers in the summer heat, but this year the heat wave is fiercer than usual and the city's inhabitants have fled to the cool of the hills and beaches of the surrounding countryside. So it is no surprise that amid the shrubbery of a normally busy roundabout, a corpse lies unnoticed, bloating in the humid air.

Sandro Cellini, meanwhile, will not be joining the crowds of holidaymakers this year. The former policeman turned private detective has a case: a man who seems to have vanished into thin air, leaving his pregnant young wife alone in the city. Bank teller Roxana Delfino is also stuck in the city for the season with nothing to do but worry about her aging mother and puzzle over the disappearance of one of her regular clients.

As all Florence sweats it out, Cellini attempts as best he can to grapple with his case and the complications it throws at him. And when the weather finally breaks, it brings with it a shocking revelation.