Rome is shattered by a series of gruesome murders that paint the Eternal City deep red. Italian Police Inspector Aristide D’Amato and his German counterpart Hans Ebert initiate their criminal investigations. They stumble upon the eccentric Professor Vassago - a master of myths and mysteries - who is linked to Senator Vinci - a corrupt politician – mutually driven by power and perversions.
The suspicion grows that these atrocious crimes are connected with the return of one of the most heinous serial killers of our time – Karl the Butcher!