Undercover agent Mark Owens (Charles Quigley) is sent to aid the Border Patrol in the trans-border town of Hernandez in breaking up a well-organized band of smugglers. Since the town is also noted for a place for obtaining quick marriages on the Mexico side, Mark obtains the job of pilot on "The Honeymoon Express." He does not realize that he has been recognized as a G-Man by "Hot Cake" Joe (Herbert Heywood), operator of a sandwich stand and an informant for the smugglers. Reporter Nancy Rawlings (Rosalind Keith), assigned to the airport on the American side of the border, sees Mike running the matrimonial express in his flamboyant uniform, and thinks he is ridiculous enough to make a good story. Her suspicions are aroused when he refuses to be photographed. She is further convinced he is a smuggler when she sees him accepting money from Kurt Feldon (Russell Hicks), suspected head of the smugglers. Feldon has accepted Mike as a genuine pilot for wedding parties and is paying him to steer customers to his cafe. Learning the truth from Joe, Feldon orders his henchman/flyer Blast Reardon (Marc Lawrence)to get rid of Mike. Blast, with a gang moll as his accomplice, charters Mike to fly them across the border to get married. A waitress at the airport, who Nancy has bribed to watch Mike's activities, tips her off about the flight and Nancy hides in the plane. Once in the air, Blast forces Mike to land at the smuggler's hideout, where he is imprisoned.

Mark Owens, a United States government undercover agent, is dispatched to the Mexican border to aid the border patrol in its effort to stop the movement of contraband into Mexico. The contraband smugglers work out of the border town of Hernandez, a favorite destination for couples who want to get married in a hurry. There, Owens, a professional pilot, gets a job flying an airplane called the "Honeymoon Express." Although Owens believes that his identity is unknown in Hernandez, he is spotted by "Hot Cake Joe," an informer for the smugglers who tends a local sandwich stand. Soon after Owens arrives in Hernandez, a border patrol aircraft is shot down by Blast Reardon, border gang leader Kurt Feldon's first lieutenant. Feldon, owner of the Raven Night Club, hires Owens to fly wedding parties to his cafe. When Nancy Rawlings, a newspaper reporter assigned to the airport beat, begins to write a story about Owens and his unusual job, she soon becomes suspicious of him when he refuses to allow his picture to be taken. After witnessing Owens accepting money from Feldon, Nancy concludes that he is in the employ of the smugglers. To learn more about his activities, Nancy pays Mamie, a waitress, to spy on Owens and report to her when his airplane leaves. Owens, meanwhile, takes photographs of the border region, hoping to discover the gang's hideout. While Owens' film is being developed, Feldon is informed of his true identity and orders Blast to kill him. After Nancy is tipped off by Mamie of Blast's plot to kidnap Owens, she hides in Owens' airplane and, undetected, flies with Blast, his moll and Owens on their flight to the gang hideout, where Owens is to be held prisoner. Concerned about Nancy's mysterious disappearance, her newspaper editor calls the border patrol. The border patrol sends a rescue team when it receives Owens' aerial photographs that reveal the location of the hideout. Meanwhile, Nancy helps Owens escape to his airplane and the two take to the air, followed by Blast in his airplane. When the border patrol airplanes arrive on the scene, an aerial dogfight ensues, resulting in the downing of Blast's airplane. The border patrol airplanes then attack and kill the rest of the gang, who are attempting to make a getaway by car. With the smugglers put out of business, Nancy and Owens decide to marry.