Dancer Angel O'Reilly (Dorothy Lamour, THE HURRICANE) is heading south of the border for love. Upon reading of the theft of the Madras Diamond, Angel realizes that her fiancé Boris (George Rigaud, A LIZARD IN A WOMAN'S SKIN) has made her an accessory to the crime and hurriedly slips the small package she has been asked by him to transport into the pocket of fellow passenger Tom Grant (Patric Knowles, THE WOLF MAN) before they must go through customs. While Tom is detained by the police, Angel goes on the run from Boris who does not believe that she has gotten rid of the diamond. Unable to return to the states, Angel racks up a hefty bill having opera singing cabbie Paolo (Mikhail Rasumny, FOR WHOM THE BELL TOLLS) drive her around to Mexico City's various night clubs in search of a job. Upon learning that Angel can sing, Paolo gets her a job at his brother-in-law's nightclub as the Condesa de Costamora. Dining at the club, Tom's attention is drawn to Angel by the rabid drooling of amorous bullfighter Manolo (Arturo de Córdova, Luis Bunuel's EL), Tom hits upon the idea to use Angel in the role of the Condesa to woo Manolo away from Tom's soon-to-be-ex-wife Helen (Ann Dvorak, SCARFACE) in hopes of patching up their marriage. Bankrolling Angel's fancy hotel room and Mexico City nightlife, Tom also schools her in everything she needs to know to pull off the act. When Tom invites the Condesa and Manolo to join him at his country hacienda - where Helen is staging a pretentious ballet on the history of Mexico with temperamental dancer Rico (Billy Daniel, who also appeared in the original MIDNIGHT) - Manolo's romantic side trip with Angel to the Xochimilco has Helen seething with jealousy. As Angel makes a public show of entertaining Manolo's overtures while fending them off when they are alone, Helen conspires with high society friend Irene (Natalie Schafer, GILLIGAN'S ISLAND's Mrs. Howell) to expose the Condesa as a fraud. Tom's and Angel's plot is further threatened by the arrival of Boris under the guise of the Conde de Costamora. As Angel tries to woo Manolo - while repelling Boris who sets his sights on Helen (more so her diamond necklace) - and Tom tries to reconcile with Helen, things start to heat up between the two conspirators just as everything may come crashing down.

Enjoyable on its own terms rather than as Paramount's uncredited "remake" of director Mitchell Leisen's own previous Claudette Colbert vehicle MIDNIGHT as a vehicle for Lamour, MASQUERADE IN MEXICO not only changes settings from Paris to Mexico but shuffles other plot elements. It makes more sense that Angel and Tom should be destined to fall for one another (which has become a romantic comedy cliche involving characters who conspire together to win the love of others), but characterization and some none-too-rigorous writing and staging of the climax make Tom into a ridiculously passive character and spurned Manolo into a "good sport" with some last minute heroics (the reunion of the lovers takes place off-camera). Performances are engaging, the production design of Roland Anderson (BREAKFAST AT TIFFANY'S) and Hans Dreier (SUNSET BOULEVARD) is as attractive as the costumes of Edith Head (VERTIGO), and the Billy Daniel's choreography and the lush staging of Helen's pagan musical a visual showstopper.