In this Mexican sci-fi fantasy, big beefy Martians invade the earth. Ostensibly, they have come to warn people about the dangers of nuclear testing and exploring space, but their real mission becomes manifest when they begin using their special powers and gadgets to exploit weak earthlings.

A peasant who works in a mahogany camp in the Mexican jungles with his family is disgusted with the miserable living conditions imposed upon himself and his co-workers, the peasant finally spearheads a revolt against the sadistic bosses.

A beautiful gypsy named Yesenia has no set path in life. During a caravan trip she meets Osvaldo who is enrolled in the militia, they both fall in love despite their differences and social prejudices.

After a young man is killed in an unexplored subterranean cavern and his girlfriend driven mad by something she saw there, a track found at the scene cannot be identified with any known animal and thus a scientific expedition is launched to find out just what it is that is living there.

Teresa is a beautiful and intelligent young woman, desperately seeking to leave the grinding poverty of the neighborhood where she lives.