Guilio Sacchi, an underworld crime boss, is about to rise above the rank of Mafia hitman to the most savage killer in Milan. He kidnaps the daughter of a wealthy businessman, planning to live a life of luxury with the ransom he collects. In the course of obtaining the money, Guilio finds it necessary to mercilessly slaughter anyone who gets in his way, and the city's death toll increases by the minute. Walter Grandi is a frustrated police chief who's seen too many innocent people die by Guilio's hands. Determined to exterminate Guilio and his men, Grandi attempts to convict the vicious criminal only to realize he can never obtain the necessary proof. Finally, Grandi must transgress the rules of his profession to stop Sacchi's ruthless reign of terror.