When airplane mechanic Dell Taylor is machine-gunned down in a Phoenix airplane hangar, Lt. Beck of the Phoenix police force questions Jay Reinhart, the owner of the crop dusting company that employed Taylor. After asserting that he has no inkling about the motive for the murder, Jay tells Beck that he was with his sweetheart, Jeanne Haggerty, a swimming instructor, on the night of the killing. Meanwhile, in Washington, D.C., the Treasury Department links Taylor to the distribution of counterfeit banknotes, which he has spent at various Phoenix nightspots with his companion, buxom nightclub singer Cameo Kincaid. When Beck interviews Jeanne about Jay's alibi, he notices her nervously twisting an unlit cigarette between her fingers. After Beck leaves, Jay comes to Jeanne's room, and she tells him that she lied for him. Manfried Stahl, Jay's accomplice, phones him there and sets up a meeting for the next day. Cameo, meanwhile, goes to Taylor's apartment to search for his stash of fake money, but she is interrupted and flees when Beck arrives to look for clues to the murder. The next day, Treasury Agent Robert Scalasi arrives in Phoenix to investigate the counterfeiting ring. Meanwhile, Stahl tells Jay to fly to Mexico and pick up a shipment of counterfeit bills. When Jay protests that he wants out, Stahl threatens to harm Jeanne unless he cooperates. Beck, on the trail of the intruder who broke into Taylor's apartment, goes to the nightclub to speak with Cameo. Cameo, however, has gone to blackmail Jay, threatening to expose his involvement with the counterfeiters unless he splits the profits with her. After Cameo departs, Jay relates her demands to Stahl, who promises to take care of her. That night, Beck returns to the nightclub to see Cameo and is joined by Scalasi, who recognizes Stahl, seated in the audience, as a fellow Treasury Agent. When Cameo appears on stage, Stahl slips behind a curtain and fires a gun at her. Bolting from the stage, Cameo jumps in her car and speeds to Jay's ranch where, at gunpoint, she takes Jeanne hostage and then orders Jay to make his pickup and hand it over to her. The next morning, Jay flies to Mexico, collects the banknotes and then drops them into a sump on his property. After retrieving the package from the sump, Stahl proceeds to the ranch-house, waves the money at Cameo and then propositions her. Cameo coolly accepts his offer, then turns and shoots Jeanne. They then climb into Stahl's convertible and speed toward the border. When Jay returns to his office, he finds Beck waiting there to question him. Jay is uncooperative until the wounded Jeanne phones the office and feebly tells him that she has been shot by Cameo and Stahl. Feeling betrayed, Jay confesses his involvement with Stahl, who as a treasury agent, was stealing old, worn out bills that were earmarked for destruction and then replacing them with fake notes. While Jay takes to the air to scan the road for Stahl's convertible, Beck follows in his squad car. After locating Stahl, Jay notifies Beck and then sprays the convertible with crop dusting chemicals to prevent Stahl from reaching the border. The car spins off the road in a cloud of dust, and when Beck arrives, he finds the car mangled and Cameo gravely injured. With her dying breath, Cameo admits to killing Taylor. Some time later, Jay, who has been released on bail at Beck's behest, picks up the now recovered Jeanne upon her release from the hospital.