Sergio Virel

A group of juvenile delinquents live a violent life in the infamous slums of Mexico City; among them Pedro, whose morality is gradually corrupted and destroyed by the others.

Out-of-work actor and his burglar pal get jobs at an agency that pledges to do things the client doesn't want to deal with. Meanwhile, their boss is being stalked by seven Italian brothers who want revenge for something that happened to their great great grandfather.

A young woman and her drug addict boyfriend plot to drive the woman's stepmother insane with LSD in a plot to secure an inheritance.

Dr. Castellanos is saved from bankruptcy.

Arácnea's residents have been desperately searching for a source of food to save the life of their queen (a big spider). Earth is chosen, since human brains are apparently like health food for alien spiders.

Maria San Carlos, the only daughter of a wealthy landowner, is betrothed to Escobar, a General in the Mexican Revolution, but she does not love him. Escobar sends a mixed gang of Americans and Mexicans to capture her and bring her to him. Complications ensue when an American cowboy, who had been hitching a ride with Maria's entourage and has his gold stolen by the gang, pursues them across the desert.

Near the end of the 19th century, Prof. John Mayer and his assistant, the scientist Dr. Isabel Reed, accidentally invent a powerful ray. An alien travels to Earth to destroy the machine since it would be a threat to the universe. He initially possesses the mind of Thomas, a sex maniac and serial killer, to get close to Mayer during the demonstration of the machine to scientists and the military. Mayer's niece, Laura, meets an acquaintance of her uncle, the chemist Dr. Paul Rosten, and Mayer invites him to join the research. When Thomas gets close to Mayer, the alien also possesses his mind in order to destroy the device and his notes. Meanwhile, Thomas is not able to control his murderous impulses and attacks several women with a straight razor.

Federico announces that his dream is to become a great singer; his father does not take it well and gradually distances himself from him. Federico is forced to leave his beautiful home after being accused of theft.