Dr. John Garth conducting an innovative medical experiment aimed at prolonging life and combating aging. The experiment takes an unexpected turn, placing the doctor in a confrontation with the ethics of his work and the consequences of his research.
Dr. Leon Kravaal develops a potential cure for cancer, which involves freezing the patient. But an experiment goes awry when authorities believe Kravaal has killed a patient. Kravaal freezes the officials, along with himself. Years later, they are discovered and revived in hopes that Kravaal can indeed complete his cure. But human greed and weakness compound to disrupt the project.
Four explorers are summoned to Peru by the brilliant physicist Dr Thorkel. They discover a rich source of radium and a half-mad Thorkel who shrinks them down to one-fifth their normal size when they threaten to stop his unorthodox experimentation.
University professor George Kingsley is struck by gangsters while crossing the street, leaving him with brain damage and one of the gangsters, Cannon, paralyzed. Kingsley's friend Dr. Sovac attends to both men, and when Cannon offers him a reward for aiding his recovery, Kovac transplants part of Cannon's brain into the dying Kingsley's skull, creating a dual personality.
When news reporter Walter Garrett arrives at the hotel room of bombshell actress Angela Merrova to conduct an interview, he finds her dead from multiple stab wounds. He returns with the police to find the hotel empty and the body vanished. Garrett writes about the incident but is fired when Merrova, alive and well, goes to the paper to complain. Now his only chance to get his job back is to find the truth, which involves the grisly scheme of a madman.
Dr. Henryk Savaard is a scientist working on experiments to restore life to the dead. When he is unjustly hanged for murder, he is brought back to life by his trusted assistant. Re-animated he turns decidedly nasty and sets about murdering the jury that convicted him.
One of the sons of late Dr. Henry Frankenstein finds his father's ghoulish creation in a coma and revives him, only to find out the monster is controlled by Ygor who is bent on revenge.
Wrongfully convicted of a robbery and murder, Paul Lavond breaks out of prison with a genius scientist who has devised a way to shrink humans. When the scientist dies during the escape, Lavond heads for his lab, using the shrinking technology to get even with those who framed him and vindicate himself in both the public eye and the eyes of his daughter, Lorraine. When an accident leaves a crazed assistant dead, however, Lavond must again make an escape.
The story of a century: a decades-long second World War leaves plague and anarchy, then a rational state rebuilds civilization and attempts space travel.
Dr. Janos Rukh discovers a certain type of radium that has almost magical healing properties. But the element has a dangerous side, too, and it has already started affecting Rukh. Consumed by paranoia, he begins to suspect that his wife is having an affair. Wild for revenge, Rukh hatches a deadly plot...using his own poisoned body as a weapon to kill.
Dr. Frankenstein and his monster both turn out to be alive after being attacked by an angry mob. The now-chastened scientist attempts to escape his past, but a former mentor forces him to assist with the creation of a new creature.
After experimenting on himself and becoming invisible, scientist Jack Griffin, now aggressive due to the drug's effects, seeks a way to reverse the experiment at any cost.
An obsessed scientist conducts profane experiments in evolution, eventually establishing himself as the self-styled demigod to a race of mutated, half-human abominations.
The villainous Dr. Fu Manchu races against a team of Englishmen to find the tomb of Ghengis Khan, because he wants to use the relics to cause an uprising in the East to wipe out the white race.
Dr. Henry Jekyll believes that there are two distinct sides to men - a good and an evil side. He believes that by separating the two, man can become liberated. He succeeds in his experiments with chemicals to accomplish this and transforms into Hyde to commit horrendous crimes. When he discontinues use of the drug, it is already too late.