When the U.S. invasion and the landing of troops in 1847 begins, the former cadet Miguel de la Peña (Jorge Negrete) and his friend Agustin Melgar (Jose Macip) decide to return to the military college and fight heroically in the defense of the Mexican army.

A South American president's daughter is kidnapped by revolutionary insurgents and taken to the jungle. He hires a group of mercs to rescue her, but a being from another planet is lurking...