Baron Victor Frankenstein is staying at a boarding house while a former fellow-scientist resides in a nearby insane asylum, slowly dying through lack of oxygen in the brain.
After discovering that the landlady's fiance has been stealing narcotics in order to support an ailing mother, Frankenstein blackmails them to help to transfer the brain of his friend into another body, thus saving him.
While he recovers, Frankenstein and the lovers relocate the Creature to a deserted manor house as the police begin to close in. The Creature awakens, and horrified by his appearance, escapes to his wife, who is too terrified to believe he is her husband. Wanting revenge, he pours paraffin around the house and allows his wife to go free.
Meanwhile, Frankenstein notices the Creature has escaped. He then finds the Creature at its wife's house where the Creature sets it alight, stating:
"...You must choose between the flames and the police, Frankenstein..."
- Peter Cushing
- Veronica Carlson
- George Pravda
- Freddie Jones
- Simon Ward
- Thorley Walters
- Windsor Davies
- Maxine Audley
- Geoffrey Bayldon
- Colette O'Neil
- Frank Middlemass
- George Belbin
- Norman Shelley
- Michael Gover
- Peter Copley
The scene where Frankenstein rapes Anna was filmed over the objections of both Peter Cushing and Veronica Carlson, and director Terence Fisher, who halted it when he felt enough was enough. It was not in the original script but the scene was added at the insistence of Hammer executive James Carreras, who was under pressure to keep American distributors happy. This explains why there is no mention of the rape subsequently by Anna or Frankenstein.
In the mid to late 1970s, the Welsh television station HTV Cymru/Wales broadcast a version dubbed into the Welsh language called Rhaid Dinistrio Frankenstein, a more-or-less literal translation of the English title. This was one of three films that were dubbed into Welsh.
Like its predecessor, Frankenstein Must Be Destroyed had lukewarm reception. While a mild treasure of the cult community, it is largely forgotten by the mainstream. The film currently holds an average 60% on Rotten Tomatoes.