When silent film stars Lucky Day, Dusty Bottoms and Ned Nederlander get fired, they take a job offer from Mexico: Doing a show with El Guapo, supposedly the most famous actor there. Traveling there in hope of getting good money, they arrive only to learn soon that El Guapo is not an actor, but a cruel gang leader suppressing people. He abducts the mayor's beautiful daughter Carmen (to be his wife) in revenge for the people's cry for help. Now, all hopes of the village folks rest on the weak shoulders of three minor-talented actors, who can't just walk off the set this time.

The infant daughter of Jack the Ripper is witness to the brutal murder of her mother by her father. Fifteen years later she is a troubled young woman who is seemingly possessed by the spirit of her father. While in a trance she continues his murderous killing spree but has no recollection of the events afterwards. A sympathetic psychiatrist takes her in and is convinced he can cure her condition. Soon, however, he regrets his decision.

An ex-con on parole and trying to straighten his life out winds up back in prison when one of his prison enemies escapes and kills his girlfriend.

The calving of an Arctic iceberg releases a giant praying mantis, trapped in suspended animation since prehistoric times. It first attacks military outposts to eat their occupants, then makes its way to the warmer latitudes of Washington and New York. A paleontologist works together with military units to try to kill it.