Pete Ritchie (Raymond Burr) runs a narcotics smuggling operation to the USA from Mexico, which the Los Angeles Police Department and the US federal government have unsuccessfully tried to stop. Because of Ritchie’s careful operating procedures, US authorities haven’t even been able to find out the identities of his sources or customers and are desperate for a breakthrough . As a last resort, Madeleine Haley (Claire Trevor), an LAPD officer, is sent undercover to Mexico to charm her way into Ritchie’s confidence.
Once there, Haley manages to establish contact with Ritchie’s gang, but is kidnapped by Johnny Macklin (Fred MacMurray), a hoodlum working for a rival of Ritchie’s and who also steals a load of Ritchie’s narcotics. Haley plays along and joins Macklin on a smuggling trip for the stolen narcotics, with Ritchie in hot pursuit.
Directed by William A. Seiter, produced by Milton H. Bren and William A. Seiter, written by Devery Freeman, starring Fred MacMurray as Johnny McEvoy (aka Johnny Macklin), Claire Trevor as Madeleine Haley (aka Gladys LaRue), Raymond Burr as Pete Ritchie, Morris Ankrum as Bill Whittaker, Roy Roberts as Harvey Gumbin, Don Diamond as Deusik Nacho Galindo as Porfirio and Pepe Hern as Pablo.