Corrado Cattani replaces the murdered Palermo chief of police Marineo.

Cattani tries to settle the score with his enemies.

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.

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!"

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.

Cattani discovers what happened the night Marineo was murdered, but the information is dangerous.

Cattani focuses his investigation on rich business men, while his private life is getting more and more difficult.

Cattani sets a trap for some of the key mafia players, resulting in the kidnapping of his only daughter.

Cattani hides the truth about his daughters disappearance from his wife and colleagues while at the same time fighting opposition in his work place.