Tony Rome (Frank Sinatra) is a P. I. While diving off in Miami in search of Spanish Galleons, Rome finds the body of a woman with her feet encased in cement in the water. He reports this to police Lieutenant Santini (Richard Conte) thinking nothing further of it until he is hired by Waldo Gronsky (Dan Blocker) to find a missing woman named Sandra Lomax, who just might be the woman he found dead. During his investigation he finds himself in contact with Kit Forrester (Raquel Welch), who hosted a party that Sandra Lomax supposedly attended. Things become complicated as Al Munger (Martin Gabel), a racketeer and friend of Kit's, starts getting bothered by Rome's intrusions. Before long Rome finds himself trying to discover a connection between all these people, which proves a difficult task.