Alerta, alta tension(1969)

After a criminal gang kidnaps a scientist with valuable information about nuclear weapons, an undercover agent named Jorge Rubio tries to infiltrate this gang in order to deal with the situation. The gang, however, quickly unmasks Rubio and uses both brainwashing and torture techniques on him. They also create a clone of Rubio, thus setting up a show-down battle between the two look-alikes.