Adventures of Giacomo Casanova

Inspector Rizzo is accused of drug trafficking. In order to clear his name he has to find out who is the person, from a Mafia ring, who has infiltrated his police department.

Bertone is a moderately honest homicide cop. Unfortunately, the court system is so inept and corrupt that many more-or-less honest policemen have begun taking the law into their own hands. Between his efforts to thwart the growth of crime and to control his vengeful co-workers, homicide-chief Bertone has his hands full

To gain fame quickly - three actors - Mino, Giacinto and Mirella, stage a fake murder (Mirella is the "victim"), then plan to find the "body" at the most opportune moment. Unfortunately, a real murder takes place in Mirella's apartment when a young woman named Margaret is killed. Having left abundant clues to the fake murder, Mino and Giacinto realise the only way to save themselves from jail is to find Margaret's killer. Despite the intrusions of a stupid police inspector, the two men discover she was killed by a mysterious "organization". Although every witness they try to question is killed by a hitman, they eventually unravel the mystery...

Baron Osvaldo Lambertenghi is forced to sell his ancestral castle, staying on as a bellboy when it's converted into a hotel. However he becomes vampirized when his mysterious uncle comes to stay.

Bruno Fioretti, known as "Mandrake", is an inveterate gambler who never misses a day at the horse racing track in Rome. He is doubly unlucky: he bets too much on one horse, and his wife is sleeping with his best friend because Mandrake is always at the track. Penniless and cuckolded, Mandrake decides to make one last bet.

The marquis Galeazzo di Torre Alta is murdered by a mysterious killer who calls himself Diabolicus. His heirs are his three brothers and a sister, but all of them, with the exception of Monsignor Antonino di Torre Alta, are killed by Diabolicus. The police are unable to solve the case, but when Antonino gives his inheritance to Pasquale Bonocore, illegitimate son of his father and Pasquale is in prison and therefore can't be the killer, all the clues are in the hand of the police.

Otello, an amateur thief, tries a burglary on New Year Eve but he finds the maid Adalgisa in the supposedly empty house. Adalgisa likes Otello who, all things considered, is a good guy, unlike Amerigo the night watchman who tries to profit from the situation.