In 1911, veteran army officer C. W. Langhorne accepts a clandestine assignment in revolutionary Mexico for the War Department along with Lieutenant Calvin Jester, a handsome young ladies' man. While Langhorne runs afoul of the Mexican secret police, Jester enjoys the attentions of both Fabiana Medina, a rich young beauty, and the poor but sincere Luna Garcia, while recovering from an injury. When danger closes in, both begin a breakneck race for the border.