Baron Wolf von Frankenstein (Basil Rathbone), the son of Henry, moves into Castle Frankenstein with his wife Baroness Elsa von Frankenstein (Josephine Hutchinson) and their young son Peter (Donnie Dunagan). He wants to restore the Frankenstein name but finds it difficult because of those unfortunate events in the district. His only friend, ironically, is Inspector Krogh (Lionel Atwill), who wears an artificial arm because the Frankenstein monster ripped his arm off when he was a child.
Getting to know the castle, he meets Ygor (Bela Lugosi), who works as a blacksmith. He is bitter because he was hanged for graverobbing and his neck is deformed. Exploring further, Wolf discovers the comatose body of the monster (Boris Karloff) in the crypt where Frankenstein’s ancestors are buried. He decides to resurrect the monster to prove his father right.
He does restore life to the monster, but it only responds to Ygor’s commands and kills several people who happen to have been jurors in Ygor’s trial. Inspector Krogh suspects Wolf has literally created a monster, but Wolf blames Ygor. Krogh doesn’t believe him and arrests him for the murder of the butler Benson (Edgar Norton) and puts him under castle arrest.
Wolf searches the property for Ygor to throw him off the property. He finds him in the laboratory. Ygor threatens Wolf with a hammer and Wolf shoots him. The monster abducts young Peter but cannot bring himself to harm the child. Krogh and Wolf pursue the monster and it tears off Krogh’s false arm. Wolf knocks the monster into a pit of molten sulphur, saving his son. He leaves the keys of the castle to the villagers and departs on the train amid their cheers.
The film was directed by Rowland V. Lee. The script written by Wyllis Cooper was rejected but his characters were kept. There were problems with the scripts and production was delayed, though it was released amid glowing reviews. They had attempted to get Peter Lorre in the cast somehow, but could not get him from 20th Century Fox, and he was playing a good guy now—Mister Moto—and did not want to be a creep anymore. Lugosi turned out to be a wonderful Ygor. Once again, the costume took a toll on Karloff. At one point, he dropped young Donnie Dunagan on the floor. But the star of the film was the gloomy, Gothic atmosphere and the eerie, expressionistic sets. Lionel Atwill’s performance as the wooden-armed Police Inspector not only inspired that of Kenneth Mars in Young Frankenstein, but I’m quite sure that of Peter Sellers as Doctor Strangelove.
The script was not well prepared and director Lee kind of made it up as he went along, but this allowed Bela Lugosi to create what is often called his best characterization. Also, he got paid more than a pittance as his role expanded. The studio knew he was desperate for money and took advantage of him. This was the last time Karloff played the monster, except for publicity stunts. The musical score, replicating the beating of a human heart, has reappeared in many horror movies. Ward Bond, of Wagon Train fame, had a small role, as did athlete Jim Thorpe. Sometimes, everything works. Let’s face it, the plot of most horror movies is ridiculous, but if enough talented people put on a straight face and play it seriously, respecting us and respecting the words they speak, coupled with some compelling music and breathtaking sets and lighting, we can be made to believe six impossible things before breakfast.