Volcanic activity frees giant scorpions from the earth who wreak havoc in the rural countryside and eventually threaten Mexico City.
| Actor | Role |
|---|---|
 Richard DenningHank Scott | Hank Scott |
 Mara CordayTeresa Alvarez | Teresa Alvarez |
 Carlos RivasArtur Ramos | Artur Ramos |
| MMario NavarroJuanito | Juanito |
 Carlos MúzquizDr. Velazco | Dr. Velazco |
 Pascual García PeñaJosé de la Cruz | José de la Cruz |
 Fanny SchillerFlorentina | Florentina |
 Arturo MartínezMajor Cosio | Major Cosio |
| PPedro GalvánFather Delgado | Father Delgado |
 José ChávezTrain conductor (uncredited) | Train conductor (uncredited) |
| MManuel Sánchez NavarroVictor Steven (uncredited) | Victor Steven (uncredited) |
 Roberto ContrerasChumacho (uncredited) | Chumacho (uncredited) |
 Quintín BulnesLineman killed on pole (uncredited) | Lineman killed on pole (uncredited) |
| IIsabel VázquezVillager (uncredited) | Villager (uncredited) |
| LLeonor GómezVillager (uncredited) | Villager (uncredited) |
 Bob JohnsonNarrator (voice) (uncredited) | Narrator (voice) (uncredited) |