When the beautiful daughter of a prominent businessman is found drunk and unconscious in a hotel room, private detective Tony Rome (Frank Sinatra) is hired to avert scandal by escorting her home. The next day, however, the girl's diamond pin is mysteriously missing, and thugs ransack Rome's houseboat in hopes of locating it. To top it all, Rome discovers his ex-partner dead in his office. One of Sinatra's most exciting screen roles, Tony Rome also features Richard Conte, Jill St. John, Sue Lyon and Gena Rowlands.

The tough, dashing private eye who lives on a boat finds his troubles beginning when, after being hired to escort the daughter of a wealthy businessman, the girl's diamond pin is mysteriously missing. The trail leads him to guns, bullets and love.