But before long the businessman is receiving threatening phonecalls, his factory is burnt to the ground and an employee loses his life. Castagnetti traces similar cases of arson across the city and realises that this sort of systematic intimidation happens when the owner's land is about to be redesignated as residential.

When Castagnetti, a bee-keeping private detective, is hired by a businessman to investigate what appears to be a simple incident of mindless vandalism, the case soon turns out to be something more sinister. Before long the businessman is receiving threatening phone-calls, his factory is burnt to the ground and an employee loses his life. As Castagnetti traces similar cases of arson across the city, it becomes clear that the construction business in northern Italy is as cut-throat as it is lucrative. Castagnetti needs to solve the case before his client, and his city, are both buried in cement.