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.