Mercedes (Marga Lopez) dances for money with the clients of Salon Mexico, a famous cabaret in Mexico City. Her younger sister Beatriz (Derbez) studies in an expensive private school, paid…

Hell-bent on revenge, cocky reform-school runaway El Jaibo returns to his old neighborhood in post-World-War-II Mexico City's poor and squalid slums, to reunite with his faithful gang of juvenile delinquents…