Sergeant Diógenes Bravo (
Cantinflas) is the Patrolman 777, a member of the Mexico City police. He has a high sense of honesty, but due to his very particular way of solving problems, he is regularly berated by his superior, Major Malagón (
Wolf Ruvinskis). While on duty, Bravo meets a group of prostitutes, among them Claudia Loza "La clarines" (
Ana Bertha Lepe) and Guadalupe "La Pingüis" (
Valeria Pani). Bravo and his partner on the force (Julio Alejandro Lobato) investigate a gang of drug traffickers led by "El Johnny" (Ramón Menéndez), who exploits the prostitutes. Many other stories take place through the course of the film, such as high-speed races in which wealthy young men participate in public roads and end in disgrace, and a robbery at a high society party. Once, while patrolling at night, Bravo stops to help a young man in a serenade, and in another case, he attends a case of domestic violence in which it is the wife (
Ofelia Guilmáin) that beats her husband, and in which Bravo has to run away before the lady ends up beating him too; and in another case, Bravo ends up going through a delivery for the first time and in the absence of the ambulance he manages to get out the baby, and even a suicide attempt to in which he has to climb the ledge of a building to rescue the suicidal man (
Fernando Luján). In the climax of the film, Bravo and his partner stop near the Tlalpan road a band from which they confiscate high-powered weapons, including grenades. Subsequently, "La Pingüis" provides information to Bravo about an illegal operation by El Johnny's gang. Bravo and his partner attend the scene, where they are received with gunshots, during which Bravo results injured. To prevent the escape of criminals, Bravo uses one of the seized grenades to blow up a truck full of drugs. Bravo is congratulated by his superiors and the film ends in a formal ceremony in which he is promoted to Lieutenant, with the police contingent activating the sirens of his vehicles as a sign of respect. ==Cast==