From the liner notes

Edwige Fenech is the policewoman Gianna, and this time she is involved in an international mission! American FBI special inspector Maccarone (or MacCarone as he says) is on the trail of a criminal boss called Big John (Aldo Maccione). Maccarone finds out that among Italian police agents there are two exact doubles of Big John's girlfriend Pupa and his little bodyguard Joe Dodiciomicidi (twelve murders). He decides to use them to infiltrate the organization, but he doesn t know that these doubles, Gianna and her assistant Alvaro Tarallo (Alvaro Vitali), cannot help but getting into troubles.