Carlos, a young man from a good family, falls prey to the drugs offered by drug dealer El Bruite. In despair, his fiancée Laura tries to help him fight his addiction. At the same time, bandits are robbing and kidnapping the region's wealthy.

Adolfo, a railroad engineer, is sent to a provincial station to investigate a series of thefts from trains. The investigation uncovers the existence of an unknown gang, led by a man named Ruby, who finds ways of committing their crimes in broad daylight. Director García Moreno received the full cooperation of the National Railroad in the making of the film, and it still stands today as a document of the great technological advances made in Mexico during the 1920s.