All ten seasons were released in Australia on DVD with English subtitles by Aztec International Entertainment, having originally aired on the Special Broadcasting Service television channel.

The plot intensifies in the fourth season, at the end of which the main protagonist, Commissioner Corrado Cattani (played by Michele Placido), is killed due to the increasing knowledge he acquires about the Mafia's vast dealings and criminal operations.

It was partly due to these political pressures that the 8th and 9th seasons deviated from telling a story set in contemporary times and shifted to the earlier era of the landowner-and-peasant mafia of the 1950s and 1960s, mainly focusing on the private affairs of the protagonists rather than on the business of Cosa Nostra, and the plot was almost entirely detached from the other chapters of the saga.

Finally, with "La piovra 10", the show strived to tie up any loose ends which were previously left pending and to present an updated perspective of the Mafia of the early 2000s.

Corrado begins an affair with the young heroin-addicted Raffaella "Titti" Pecci Scialoia (Barbara De Rossi), whose mother was shot together with former police commissioner Marineo.

The season additionally features the powerful architect Olga Camastra (Florinda Bolkan) and the commissioner's primary antagonist, attorney Terrasini (François Périer).

For this purpose, Colonel Ettore Ferretti (Sergio Fantoni), a connection to Corrado's long-time friend and mentor Sebastiano Cannito (Jacques Dacqmine), makes an appearance.

The corrupt Cannito has gained a high position in the Secret Service with the help of the Masonic lodge and is deeply involved in the business of the Mafia, which Ferretti wants to uncover.

Cattani is forced to agree to a pact with his foe, and he goes undercover as an assistant to the powerful Cannito; in this role he has to work closely with the people responsible for the death of several of his colleagues.

Gaetano "Tano" Cariddi (Remo Girone), the most notorious mafia character of the series, initially holds the role of assistant at the Antinari Bank, before becoming its sole owner at the end of the season.

The investigation into the case of the mysterious murder of a casino owner, Carmelo Tinadari, has been entrusted to a new judge - the legendary Silvia Conti (Patricia Millardet), with whom Cattani initially quarrels, but later has a love affair.

The two main links to the previous story include the judge Silvia Conti, who wants to find the murderers of Corrado Cattani, and head mobster Tano Cariddi, who continues to engage in criminal activities.

Licata is now recruited by the American police in New York City and smuggled undercover into the immediate vicinity of Sicilian entrepreneur Giovanni Linori (Luigi Pistilli) in Palermo.

New Mafia head Don Amilcare Attilio Brenno (Pierre Mondy) makes his fortune by bribing foreign companies as part of development aid to Africa.

Davide Licata, back for another season, barely gets away with his life in an assassination attempt ordered by Brenno, and sustains a permanent injury, with a bullet that can no longer be removed from his skull and which causes him violent headaches.

Meanwhile, Tano Cariddi, suffering from severe drug addiction and depression, is located in Dakar, Senegal by Licata and brought back to Italy to act as a key witness against the Mafia.

The season continues with various plots and sub-plots, Mafia rivalries and schisms, Turkish drug-running channels, and even a connection with a former Nazi concentration camp supervisor in Czechoslovakia.

This latter, played by renowned Czech actor Rudolf Hrušínský in his last major role, escaped the Allied liberation forces at the end of World War II by assuming the identity of a camp prisoner, and later went on to become a wealthy banker using stolen Jewish money.

Luigi Perelli again directed, the setting was brought back to Trapani, and Countess Olga Camastra (Florinda Bolkan) reappeared, in order to re-establish continuity with the story of Corrado Cattani, whose life had been cut short at the end of the fourth season.

The plot begins with the murder of Rosario Granchio, a Sicilian criminal from the immediate vicinity of Don Nazzareno "Nuzzo" Marciano (Stefan Danailov), the local mafia boss who controls a large part of the protection funds in Palermo.

Other actors from previous seasons also reappeared, most notably Renato Mori, once in the role of Vice-Commissioner Giuseppe Altero, partner to Corrado Cattani, now as the aging mafia boss Don Calogero Albanese.

The power-hungry Pietro Favignana (Luca Zingaretti) kills the aging Don Albanese and rapes his daughter Rosario (Daniela "Mietta" Miglietta), forces her to marry him, and thus becomes the new mob boss.

In order to blackmail him and his wife Baroness Barbara Greenberg Altamura (Anja Kling), Favignana kidnaps their son Paul and has the young Tano "Tanuzzo" Cariddi guard him on an abandoned estate.

Finally, eager to learn and grow, Tano convinces Francesco Altamura to send him to a prestigious school and look after his half-sister Maria; in a season-finale twist, it is revealed that her father was Pietro Favignana himself.

Luigi Perelli returned to direct the final chapter of the series, and the screenplay was written by producer Sergio Silva, with Mimmo Rafele and Piero Bodrato; the soundtrack was again composed by Ennio Morricone.

Investigative judge Silvia Conti (Patricia Millardet) watches Ramonte giving his first television interview on the steps of the courthouse, in which he openly threatens his enemies.

Giulia Mercuri (Elena Arvigo), daughter of Thule's chief financial officer, finds out about her father's criminal dealings and about Ramonte's involvement in Corrado Cattani's murder, and she reveals this to Silvia Conti.

The largest group of viewers was demographically similar to the figure of Corrado Cattani himself: "a man of average age from the big cities of northwestern Italy", especially Milan and Turin.

Conservative politician Silvio Berlusconi and others from Forza Italia as well as representatives from Democrazia Cristiana claimed that shows like La Piovra were responsible for "Italy's negative image abroad" and demanded that it cease filming.

The cause of the conflict was an interview with leading actor Remo Girone,[12] who explicitly made a connection between the final season's plotline, in which the boss of a secret criminal organization is acquitted of his crimes, and the pressure exerted in Italy on judges in mafia trials.