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.