Francesco Rosi utilizes the breathtakingly beautiful Italian landscape in an unspecified Italian city to hatch this mystery film involving murder and corruption in high places. As the film begins, a well-known prosecutor is killed. The murder turns out to be the first in a series of murders -- and all the victims are judges.
With Italy lapsing into chaos because of the crimes, the craggy and careworn Inspector Rogas (Lino Ventura) is brought in to solve the murders. Rogas thinks that a man, sent to prison for a crime he didn't commit, is the person responsible for the killings. But when Rogas reports that fact to his superiors, they want nothing to do with the case.
When more killings occur, Rogas uncovers a plot involving his superiors who are using one man's revenge murder as a ploy in order to affect nefarious changes on the entire country.