Plot:
Grave digging by night, no good can come of it. The local constable on patrol hears a commotion. The grave robber gets the corpse and distracts the cop to escape. He gets the corpse to Simon Helder. Grave robber warns him of being caught. The corpse snatcher may be scared of Helder’s work but still wants his pay.
Grave robber heads to the nearby pub. The cop comes in. The grave robber wants to tell him something before going to jail.
Simon is in his lab with his “Collected Works of Baron Frankenstein.” He sees the cops approach. The lab work is covered up. The cop knocks on the door but eventually breaks it while Simon hides in the dark room. The cop lights a nearby lamp, finding the stolen corpse. Simon is still hiding as the cop picks up a jar of eyes. Wonder if they’ll get dropped? Simon makes his appearance. And the eyes are promptly dropped on the floor.

Why you shouldn't spill a jar of eyes on the floor.
Simon is worried about them. The cop wants to know what the bodies are about to be used for? Simon calmly explains he’ll stitch them together to create a new man. The cop arrests him for sorcery.
At the trial, the judge lectures Simon for his vile crime. We learn that Simon is actually a medical doctor. Frankenstein was sentenced by the same court years ago. Dr. Simon will be sent to the state asylum for 5 years before checking if he is to be released.
Simon is taken to the asylum. He is shackled and taken inside. Simon manages to meet the director. Simon starts questioning the director, who thinks Simon is an inspecting doctor. Learns that Frankenstein died years ago. The director is angry when learning that Simon is an inmate.
Simon is taken away by the attendants. He is to be initiated. The inmates are brought in to watch Simon. Simon’s shirt is ripped off and he is hosed down with a high pressure hose. The inmates think this is funny except for dark headed chick. Simon is starting to bleed from his back. When Peter Cushing arrives to save the day, he sends the patients away. He has Sarah, the dark headed chick to take Simon and patch him up. Peter has a talk with the attendants.
Peter Cushing marches to the director’s office, chewing him out. The attendants outside overhear the argument. Peter sends, Gerda, the girl the director was examining back to her room. Cushing threatens to leave Frankenstein is dead; he can leave whenever he wants to leave. He came to complain about the treatment of Simon. The attendants are brought in to be punished. The director is Peter Cushing’s boy. Cushing came back early because the medical supplies last shipment weren’t paid for yet. Director explains how the state is specific in what it pays for. The director is embezzling funds for himself. He will take care of the medical supply payments by tomorrow. Cushing leaves.
Simon is being bandaged by Sarah. She doesn’t answer him. Peter Cushing arrives and fixes Simon a drink. He starts checking Simon’s reflexes. Sarah leaves. Simon knows he is Frankenstein. Cushing explains that Frankenstein is dead. He is Dr. Carl Victor. Victor has enough material to blackmail the director and the staff. Simon is to assist him with his practice. Simon will take over tending to the inmates. Victor will spend more time on his private work.
The director meets Cushing who has found an assistant. The director is less than happy to learn it is Simon.
Cushing and Sarah show Simon around. Sarah will aid Simon when duties don’t have her aid Cushing.
Cushing watches as Simon begins treating the patients. Some patients Dr. Victor will keep treating. Simon is showed these special patients. 1 is super strong before he died. Another is a professor that seems very educated. Dr. Victor claims he attacked the director. The next is skilled carver whose brain has atrophied. All the patients think highly of Sarah.
Simon is to now take care of the regular patients.
That night, Simon hears Dr. Victor working. The next morning, Simon sees a funeral in the cemetery. A pallbearer trips, topples the coffin. It is the dead carver with both of his hands missing. Dr. Victor gets the lid back on the coffin. Simon realizes that Peter Cushing is back up to his old tricks.
Night, the violin playing professor hears other inmates.
Simon is taking a walk and goes to the examining room. He starts looking for a secret passage but gives up. Sarah leaves the passageway. He follows her back inside. Sarah runs away. Simon looks at the medical diagrams of brains when Peter Cushing arrives demanding to know what he’s doing. Simon has figured out that Frankenstein is back to his old tricks. Cushing reveals his latest creation using the body of the super-strong inmate that died. Simon knows the carver’s hands were put on the body.
Simon looks over the Monster from Hell. We learn that Cushing is unable to operate with his scarred hands. Sarah followed Cushing’s directions for the surgery. Simon wants to help him with this experiment.
The surgery begins as Cushing oversees Simon. Cushing later inspects new eyes for the creature.

Eye pick you.
Creature has the new eyes transplanted. Cushing is happy with Simon’s surgical skill.

Just pop it back in...
Creature awakens seeing Sarah in the distance. Simon and Cushing are working. Everyone sees the Creature is awake and the eye transplants seem to be working fine. Cushing gasses the Creature to sleep.
Cushing explains the Creature hates him for keeping him alive. The next stage requires the brain of a genius to be transplanted into the Creature. The only genius around is Professor Durandel who could live for another 10, 20 years. Simon is shocked that the Durandel would be killed to get his brain. Cushing would never kill to get the professor’s brain.
Attendant brings a meal to Durandel, discovering the professor has hanged himself.
Simon tells Cushing about the apparent suicide of Durandel. They spring into action. Simon begins the brain transplant, removing the Durandel’s brain. Cushing watches anxiously as Simon cuts the brain free. The brain is placed in aquarium like jar temporarily.
Hours later, Simon finds a note for Durandel stating he’ll never leave the asylum. The note provoked him to commit suicide because Cushing needed his brain.
Transplant the brain to the Creature. It will take some time before they learn if the operation was a success. Simon leaves to get some rest while Cushing waits to see it everything he’s done over the years will be justified by his creation.
Creature awakens with the Durandel’s brain. He realizes this is not his hands or body. He stumbles through the lab and sees his face. Sarah runs off to alert Cushing. Cushing, Simon, and Sarah find Durandel downcast before he talks with Cushing.
Simon wants to celebrate Cushing’s accomplishment. Professor Creature keeps questioning why he was made.
Professor Creature tries playing the violin. But, he tears it apart in the process. Cushing wants to keep Durandel’s mind sharp by relearning to write in his new body. Cushing orders him around all the time.
The experiment is a failure. The body is rejecting Durandel’s brain. Simon goes to check of Professor Creature. He is obviously attracted to Sarah. She leaves the lab.
Creature tries throwing glass barely missing Simon. Cushing comes to the rescue. Ever want to see Peter Cushing ride Piggy-back on Darth Vader? Here’s your chance. Cushing gasses the Creature unconscious. Durandel is caged again.
Cushing has a deep revelation. The body is taking over the brain. He has a new idea: mate the Creature with Sarah. Sarah is mute by traumatic stress. Her father tried to rape her. Simon will take Sarah to the Director for protection. Cushing reveals she is the director’s daughter. Durandel attacked the Director after learning it himself. Cushing is using it to blackmail the Director to do whatever he needs done. Cushing heads to town.
Creature is in the cage. Simon tries talking with him. Simon gets the Creature his food but spikes it with poison first. Creature greedily eats before falling over. Simon grabs a scalpel to jimmy the lock open. Creature grabs Simon. Sarah arrives and actually speaks for the first time in the movie ordering him to release Simon. Sarah and Simon get out of there.
Sarah wants Simon to get help. Cushing returns discovering the Creature is free. Attendants spot the Creature outside digging up graves. The inmates are loose, too. It’s a genuine madhouse without John Laroquette.
Director and his trollop come to the asylum for a night of festivities. Attendants tell him about someone demolishing graves. He sees the Creature in the cemetery, too. The director has the guards get guns from the armory to kill the monster.
Director is loading up on liquid courage. Creature breaks into his office, killing him.
Inmates see the Creature. Attendants open fire hitting the Creature. Simon holds Sarah safely away. Creature holds it hand out for Sarah to touch. The inmates attack the Creature fearing for Sarah’s safety.
Cushing orders the inmates to stop. Seeing the dead Creature, he has the inmates return to their cells. Simon helps to bandage Cushing’s arm.
Cushing considers the next experiment with Simon’s help. He begins cleaning the lab up.