THE REVENGE OF FRANKENSTEIN

In 1860, Baron Victor Frankenstein, sentenced to death, escapes execution by the guillotine by having a priest beheaded and buried in his place with the aid of a hunchback named Karl. Three years later, Victor, now going by the alias Doctor Stein, has become a successful physician in Carlsbrück, catering to the wealthy while also attending to the poor in a paupers' hospital. Hans Kleve, a junior member of the medical council, recognises Victor and blackmails him into allowing him to become his apprentice. Together with Karl, Victor and Hans continue with the Baron's experiment: transplanting a living brain into a new body, one that is not a crude, cobbled-together creature. The deformed Karl is more than willing to volunteer his brain thereby gaining a healthy body, particularly after meeting Margaret, the lovely new assistant at the hospital.

The transplant succeeds, but when the excited Hans tells Karl that he will be a medical sensation, Karl panics and convinces Margaret to free him. Hans notes that the chimpanzee into which Victor had transplanted the brain of an orangutan ate its mate and worries about Karl, but his concerns are brushed off by Victor. Karl flees from the hospital and hides in Victor’s laboratory, where he burns his preserved hunchback body. He is attacked by a drunken janitor, who takes him for a burglar, but manages to kill the man. Victor and Hans discover Karl is missing and begin searching for him.

The next morning, Margaret finds Karl in her aunt's stable. While she goes to fetch Hans, Karl experiences difficulties with his arm and leg. When Hans and Margaret arrive, he is gone. At night, Karl ambushes and strangles a local girl. The next night, he rushes into an evening reception. Having redeveloped his deformities, he begs Victor for help, using his real name of Frankenstein, before he collapses and dies. Victor, disregarding Hans' pleas that he should leave the country, appears before the medical council, where he denies being the infamous Frankenstein. The unsatisfied councilors open Victor's supposed grave, only to discover the priest's body, and conclude that the real Frankenstein is still alive.

At the hospital, the patients violently attack Victor out of fear, and Hans rushes his dying mentor to the lab. The police arrive to arrest Victor, but when Hans shows them Victor's dead body, they leave. Hans then transplants Victor's brain into a new body that Victor had prepared earlier, which he made to resemble him. Sometime later in London, Hans assists Victor, now calling himself Doctor Franck, in welcoming some patients.

Baron Frankenstein, working under the protective pseudonym Dr. Victor Stein, together with his assistant Dr. Kleve, transplants a dwarf's brain into another body and unleashes a deranged being.