Ambitious young woman decides to leave her backwards hometown and move to Mexico City to study for a scientific degree.

While attending the birth of Isabel, the wife of foreigner Felipe, Mama Santos predicts that "something terrible is going to happen in the town." From this omen, calamities will torment the locals.

La India María, who is really good at sports, becomes a nun and is always getting in trouble for wanting to help people.

Dave Boland (Carlos East) wears a strange medallion and robs the bank. He also takes the banker's daughter with him. Then he rapes her and put the satanic mark on her body. He was caught and was prepared for hanging. At moment before hanging Dave uses his supernatural power and makes a local shoe-shiner his accomplice. While running from sheriff Dave was injured and after some time dies. But before his death Dave gives this medallion to shoe-shiner Oscar and asks him to take revenge in the name of Satan. So he does it and also continue to rape and kill women never forgetting to leave satanic mark on their bodies...

Wild-partying hippie-artist-dilettantes end up forming a revolutionary terrorist cell. The misfit Gato loses a lot of money in bets and his father throws him out of his house. Ál leaves his girlfriend Laura for his lover, the married Adriana. Out of money Gato and Ál becomes urban guerrilla when they plan to kidnap Gato's rich father.