Police Inspector Cattani fights a losing battle to save his loved daughter's sanity, after what she suffered (see "La Piovra", original mini-series). He loses her, and his only trusted magistrate in the fight against The Octopus.

Cattani is approached by the Number 2 of his best friend in Rome to conspire against him, and ends up fighting for his life in prison, against thugs who are friends of his worst enemy. Cattani must swallow his pride, and recurs to the lustful Contessa who has other friends in common.

Cattani's love life is as confused as his behaviour; he sleeps with the enemy, and is recruited to ITALA, the cultural association for the study of the ancestral popular traditions of Italy, The Octopus by another name.

It leaves an acrid taste in Cattani's mouth, as he loses yet another important ally, and severes his ties with the beautiful Contessa, when he wakes up fire in enemy ground.

Cattani's major achievement so far leaves him without friends in Rome; his former teacher explains between whiskeys how easy it is for an intelligent man to fall into criminal ambition.

Cattani's takes one year leave without pay from his desk job at the Intelligence Services, and then destiny presents him with a couple of revenge opportunities against the tandem of corrupt politicians and mafia expatriates, again at heavy personal cost.

After the mafia killed his family, and a number of people who trusted him, Cattani sees a couple of criminals condemned to light sentences only. A DEA team brings him back from the mountain retreat with good monks, to the evil world of a drugs-for-arms deal. Solace comes in the form of new affections for a banker's daughters, who look like his lost wife and daughter.

Cattani uses a TV interview to reveal he found out about one of The Octopus telephone numbers. That is enough to spread havoc in the criminal rang, but the mafia leaves the American investigators no escape.

Cattani falls in love with Giulia, but his inquest does not go far, until Giulia's father dies, and her grandfather takes hold of the family bank again.

The Antinari bank is backing the illegal arms deal, trusted friends and servants may not be what they seem, and Cattani is undecided between personal vendetta and life in a monastery.

Anna Antinari gets hold of documents that are essential for the arms deal, and trusts her life and that of her child daughter Greta to the good monks who were already hosting Cattani. For the mafia in liaison with a member of parliament, monastery walls are no protection against a new massacre.

Cattani meets Giulia again at her mother's funeral, and research and luck bring him up North to Rome, in order to discover the way to the South again, from where a ship will depart with an illegal arms cargo.

Giulia reconciles with her grandfather Nicola, and her second meeting with chief inspector Corrado Cattani is yet a probe for his loyalty to duty. One man ends a life of power tragically; the other hangs desperately to life because, as Giulia says, "He lost; and quite a lot!"

Judge Silvia Conti and Davide Licata are in a quest for vengeance against the Mafia.

Police detective Davide Licata survives badly wounded, so much so that his personal and love life will be affected.

Licata is tempted by the General directing the Government's "nucleous of operations and investigations (NOI)", a secret service built to do the dirty anti-crime jobs that the police can't do.

The hideout of Tani Cariddi in deep Africa becomes known - and again, the retired detective and the retired criminal must come to grips with violent action in Europe.

Not one but several traps are set from both sides of the law.

A desperate chase is given by The Core and two countries magistrates to catch the new drug lords that are aiming at deluging drugs into Europe's Eastern countries from a former Nazi concentration camp in the West.

The detective exposes and destroys the man who secretively had taken the place of the octopus's head - but the crime will not stop, because the criminal's son escapes with enough power to restart it all.

Several characters return to the little town where, years ago, the police commissary Cattani was set up and murdered by the Mafia.

Sara and Biagio, her brother, create an extortion gang, named after the village's suburbs where they live. They are taking the "business" out of Nuzzio's hands.

Saverio comes home to reunite with Nuzzio against the higher powers of the Mafia, but these are alert and after him, after torturing his mistress in St. Petersburg. Also after him, is his wife, still under the protection of Oleg, Saverio's bodyguard.

The local television channel, owned by Olga Camastra, puts the blame of her husband's death on Silvia Conti's harsh interrogation of the old man. Saverio's ascension to power seems unstoppable: he masters over Nuzzio with his superior intelligence, and helps him escape an ambush; the Barrotti gang is massacred by Nuzzio's men; and he breaks and enters into the countess's palace, frightening her, and demanding the names list.

Silvia is blamed for another strange death, the young commissary Breda is sent away to his hometown far north - something he had requested before he was into this case - and their only witness, Sara, is pressed by a police inspector and the new prosecutor to deny her earlier testimony.

The killing attempt worked almost to perfection, and more blood runs in the streets. Silvia Conti's life is spared due to the intervention of Oleg, Saverio's bodyguard, who decided against Nuzzio's opinion that she would be more valuable to them alive.