The FBI hires a former mafia hit man (James Coburn) to track down and bring in a powerful reclusive billionaire suspected of criminal acts for his own benefit. The man also comes into a conflict with a woman (Sophia Loren) tracking down the same crook for revenge reasons.

According to director Michael Winner, producer Lew Grade had fully expected Charles Bronson to co-star with Loren. With much of the pre-production crew already on location in the Caribbean, Grade wanted to shut down the production when Bronson pulled out. Realizing how much money he had already sunk into a film that had not properly secured its star actors, Grade saved face by moving ahead using James Coburn as a replacement for Bronson.[2]